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CHANGELOG.md
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### ClickHouse release v21.11, 2021-11-09
#### Backward Incompatible Change
* Change order of json_path and json arguments in SQL/JSON functions (to be consistent with the standard). Closes [#30449](https://github.com/ClickHouse/ClickHouse/issues/30449). [#30474](https://github.com/ClickHouse/ClickHouse/pull/30474) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Remove `MergeTree` table setting `write_final_mark`. It will be always `true`. [#30455](https://github.com/ClickHouse/ClickHouse/pull/30455) ([Kseniia Sumarokova](https://github.com/kssenii)). No actions required, all tables are compatible with the new version.
* Function `bayesAB` is removed. Please help to return this function back, refreshed. This closes [#26233](https://github.com/ClickHouse/ClickHouse/issues/26233). [#29934](https://github.com/ClickHouse/ClickHouse/pull/29934) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* This is relevant only if you already started using the experimental `clickhouse-keeper` support. Now ClickHouse Keeper snapshots compressed with `ZSTD` codec by default instead of custom ClickHouse LZ4 block compression. This behavior can be turned off with `compress_snapshots_with_zstd_format` coordination setting (must be equal on all quorum replicas). Backward incompatibility is quite rare and may happen only when new node will send snapshot (happens in case of recovery) to the old node which is unable to read snapshots in ZSTD format. [#29417](https://github.com/ClickHouse/ClickHouse/pull/29417) ([alesapin](https://github.com/alesapin)).
#### New Feature
* New asynchronous INSERT mode allows to accumulate inserted data and store it in a single batch in background. On client it can be enabled by setting `async_insert` for `INSERT` queries with data inlined in query or in separate buffer (e.g. for `INSERT` queries via HTTP protocol). If `wait_for_async_insert` is true (by default) the client will wait until data will be flushed to table. On server-side it controlled by the settings `async_insert_threads`, `async_insert_max_data_size` and `async_insert_busy_timeout_ms`. Implements [#18282](https://github.com/ClickHouse/ClickHouse/issues/18282). [#27537](https://github.com/ClickHouse/ClickHouse/pull/27537) ([Anton Popov](https://github.com/CurtizJ)). [#20557](https://github.com/ClickHouse/ClickHouse/pull/20557) ([Ivan](https://github.com/abyss7)). Notes on performance: with asynchronous inserts you can do up to around 10 000 individual INSERT queries per second, so it is still recommended to insert in batches if you want to achieve performance up to millions inserted rows per second.
* Add interactive mode for `clickhouse-local`. So, you can just run `clickhouse-local` to get a command line ClickHouse interface without connecting to a server and process data from files and external data sources. Also merge the code of `clickhouse-client` and `clickhouse-local` together. Closes [#7203](https://github.com/ClickHouse/ClickHouse/issues/7203). Closes [#25516](https://github.com/ClickHouse/ClickHouse/issues/25516). Closes [#22401](https://github.com/ClickHouse/ClickHouse/issues/22401). [#26231](https://github.com/ClickHouse/ClickHouse/pull/26231) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added support for executable (scriptable) user defined functions. These are UDFs that can be written in any programming language. [#28803](https://github.com/ClickHouse/ClickHouse/pull/28803) ([Maksim Kita](https://github.com/kitaisreal)).
* Allow predefined connections to external data sources. This allows to avoid specifying credentials or addresses while using external data sources, they can be referenced by names instead. Closes [#28367](https://github.com/ClickHouse/ClickHouse/issues/28367). [#28577](https://github.com/ClickHouse/ClickHouse/pull/28577) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added `INFORMATION_SCHEMA` database with `SCHEMATA`, `TABLES`, `VIEWS` and `COLUMNS` views to the corresponding tables in `system` database. Closes [#9770](https://github.com/ClickHouse/ClickHouse/issues/9770). [#28691](https://github.com/ClickHouse/ClickHouse/pull/28691) ([tavplubix](https://github.com/tavplubix)).
* Support `EXISTS (subquery)`. Closes [#6852](https://github.com/ClickHouse/ClickHouse/issues/6852). [#29731](https://github.com/ClickHouse/ClickHouse/pull/29731) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Session logging for audit. Logging all successful and failed login and logout events to a new `system.session_log` table. [#22415](https://github.com/ClickHouse/ClickHouse/pull/22415) ([Vasily Nemkov](https://github.com/Enmk)) ([Vitaly Baranov](https://github.com/vitlibar)).
* Support multidimensional cosine distance and euclidean distance functions; L1, L2, Lp, Linf distances and norms. Scalar product on tuples and various arithmetic operators on tuples. This fully closes [#4509](https://github.com/ClickHouse/ClickHouse/issues/4509) and even more. [#27933](https://github.com/ClickHouse/ClickHouse/pull/27933) ([Alexey Boykov](https://github.com/mathalex)).
* Add support for compression and decompression for `INTO OUTFILE` and `FROM INFILE` (with autodetect or with additional optional parameter). [#27135](https://github.com/ClickHouse/ClickHouse/pull/27135) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Add CORS (Cross Origin Resource Sharing) support with HTTP `OPTIONS` request. It means, now Grafana will work with serverless requests without a kludges. Closes [#18693](https://github.com/ClickHouse/ClickHouse/issues/18693). [#29155](https://github.com/ClickHouse/ClickHouse/pull/29155) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Queries with JOIN ON now supports disjunctions (OR). [#21320](https://github.com/ClickHouse/ClickHouse/pull/21320) ([Ilya Golshtein](https://github.com/ilejn)).
* Added function `tokens`. That allow to split string into tokens using non-alpha numeric ASCII characters as separators. [#29981](https://github.com/ClickHouse/ClickHouse/pull/29981) ([Maksim Kita](https://github.com/kitaisreal)). Added function `ngrams` to extract ngrams from text. Closes [#29699](https://github.com/ClickHouse/ClickHouse/issues/29699). [#29738](https://github.com/ClickHouse/ClickHouse/pull/29738) ([Maksim Kita](https://github.com/kitaisreal)).
* Add functions for Unicode normalization: `normalizeUTF8NFC`, `normalizeUTF8NFD`, `normalizeUTF8NFKC`, `normalizeUTF8NFKD` functions. [#28633](https://github.com/ClickHouse/ClickHouse/pull/28633) ([darkkeks](https://github.com/darkkeks)).
* Streaming consumption of application log files in ClickHouse with `FileLog` table engine. It's like `Kafka` or `RabbitMQ` engine but for append-only and rotated logs in local filesystem. Closes [#6953](https://github.com/ClickHouse/ClickHouse/issues/6953). [#25969](https://github.com/ClickHouse/ClickHouse/pull/25969) ([flynn](https://github.com/ucasfl)) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add `CapnProto` output format, refactor `CapnProto` input format. [#29291](https://github.com/ClickHouse/ClickHouse/pull/29291) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow to write number in query as binary literal. Example `SELECT 0b001;`. [#29304](https://github.com/ClickHouse/ClickHouse/pull/29304) ([Maksim Kita](https://github.com/kitaisreal)).
* Added `hashed_array` dictionary type. It saves memory when using dictionaries with multiple attributes. Closes [#30236](https://github.com/ClickHouse/ClickHouse/issues/30236). [#30242](https://github.com/ClickHouse/ClickHouse/pull/30242) ([Maksim Kita](https://github.com/kitaisreal)).
* Added `JSONExtractKeys` function. [#30056](https://github.com/ClickHouse/ClickHouse/pull/30056) ([Vitaly](https://github.com/orloffv)).
* Add a function `getOSKernelVersion` - it returns a string with OS kernel version. [#29755](https://github.com/ClickHouse/ClickHouse/pull/29755) ([Memo](https://github.com/Joeywzr)).
* Added `MD4` and `SHA384` functions. MD4 is an obsolete and insecure hash function, it can be used only in rare cases when MD4 is already being used in some legacy system and you need to get exactly the same result. [#29602](https://github.com/ClickHouse/ClickHouse/pull/29602) ([Nikita Tikhomirov](https://github.com/NSTikhomirov)).
* HSTS can be enabled for Clickhouse HTTP server by setting `hsts_max_age` in configuration file with a positive number. [#29516](https://github.com/ClickHouse/ClickHouse/pull/29516) ([凌涛](https://github.com/lingtaolf)).
* Huawei OBS Storage support. Closes [#24294](https://github.com/ClickHouse/ClickHouse/issues/24294). [#29511](https://github.com/ClickHouse/ClickHouse/pull/29511) ([kevin wan](https://github.com/MaxWk)).
* New function `mapContainsKeyLike` to get the map that key matches a simple regular expression. [#29471](https://github.com/ClickHouse/ClickHouse/pull/29471) ([凌涛](https://github.com/lingtaolf)). New function `mapExtractKeyLike` to get the map only kept elements matched specified pattern. [#30793](https://github.com/ClickHouse/ClickHouse/pull/30793) ([凌涛](https://github.com/lingtaolf)).
* Implemented `ALTER TABLE x MODIFY COMMENT`. [#29264](https://github.com/ClickHouse/ClickHouse/pull/29264) ([Vasily Nemkov](https://github.com/Enmk)).
* Adds H3 inspection functions that are missing from ClickHouse but are available via the H3 api: https://h3geo.org/docs/api/inspection. [#29209](https://github.com/ClickHouse/ClickHouse/pull/29209) ([Bharat Nallan](https://github.com/bharatnc)).
* Allow non-replicated ALTER TABLE FETCH and ATTACH in Replicated databases. [#29202](https://github.com/ClickHouse/ClickHouse/pull/29202) ([Kevin Michel](https://github.com/kmichel-aiven)).
* Added a setting `output_format_csv_null_representation`: This is the same as `output_format_tsv_null_representation` but is for CSV output. [#29123](https://github.com/ClickHouse/ClickHouse/pull/29123) ([PHO](https://github.com/depressed-pho)).
* Added function `zookeeperSessionUptime()` which returns uptime of current ZooKeeper session in seconds. [#28983](https://github.com/ClickHouse/ClickHouse/pull/28983) ([tavplubix](https://github.com/tavplubix)).
* Implements the `h3ToGeoBoundary` function. [#28952](https://github.com/ClickHouse/ClickHouse/pull/28952) ([Ivan Veselov](https://github.com/fuzzERot)).
* Add aggregate function `exponentialMovingAverage` that can be used as window function. This closes [#27511](https://github.com/ClickHouse/ClickHouse/issues/27511). [#28914](https://github.com/ClickHouse/ClickHouse/pull/28914) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow to include subcolumns of table columns into `DESCRIBE` query result (can be enabled by setting `describe_include_subcolumns`). [#28905](https://github.com/ClickHouse/ClickHouse/pull/28905) ([Anton Popov](https://github.com/CurtizJ)).
* `Executable`, `ExecutablePool` added option `send_chunk_header`. If this option is true then chunk rows_count with line break will be sent to client before chunk. [#28833](https://github.com/ClickHouse/ClickHouse/pull/28833) ([Maksim Kita](https://github.com/kitaisreal)).
* `tokenbf_v1` and `ngram` support Map with key of String of FixedSring type. It enhance data skipping in query with map key filter. ```sql CREATE TABLE map_tokenbf ( row_id UInt32, map Map(String, String), INDEX map_tokenbf map TYPE ngrambf_v1(4,256,2,0) GRANULARITY 1 ) Engine=MergeTree() Order by id ``` With table above, the query `select * from map_tokebf where map['K']='V'` will skip the granule that doesn't contain key `A` . Of course, how many rows will skipped is depended on the `granularity` and `index_granularity` you set. [#28511](https://github.com/ClickHouse/ClickHouse/pull/28511) ([凌涛](https://github.com/lingtaolf)).
* Send profile events from server to client. New packet type `ProfileEvents` was introduced. Closes [#26177](https://github.com/ClickHouse/ClickHouse/issues/26177). [#28364](https://github.com/ClickHouse/ClickHouse/pull/28364) ([Dmitry Novik](https://github.com/novikd)).
* Bit shift operations for `FixedString` and `String` data types. This closes [#27763](https://github.com/ClickHouse/ClickHouse/issues/27763). [#28325](https://github.com/ClickHouse/ClickHouse/pull/28325) ([小路](https://github.com/nicelulu)).
* Support adding / deleting tables to replication from PostgreSQL dynamically in database engine MaterializedPostgreSQL. Support alter for database settings. Closes [#27573](https://github.com/ClickHouse/ClickHouse/issues/27573). [#28301](https://github.com/ClickHouse/ClickHouse/pull/28301) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added function accurateCastOrDefault(x, T). Closes [#21330](https://github.com/ClickHouse/ClickHouse/issues/21330). Authors @taiyang-li. [#23028](https://github.com/ClickHouse/ClickHouse/pull/23028) ([Maksim Kita](https://github.com/kitaisreal)).
* Add Function `toUUIDOrDefault`, `toUInt8/16/32/64/256OrDefault`, `toInt8/16/32/64/128/256OrDefault`, which enables user defining default value(not null) when string parsing is failed. [#21330](https://github.com/ClickHouse/ClickHouse/pull/21330) ([taiyang-li](https://github.com/taiyang-li)).
#### Performance Improvement
* Background merges can be preempted by each other and they are scheduled with appropriate priorities. Now long running merges won't prevent short merges to proceed. This is needed for a better scheduling and controlling of merges execution. It reduces the chances to get "too many parts" error. [#22381](https://github.com/ClickHouse/ClickHouse/issues/22381). [#25165](https://github.com/ClickHouse/ClickHouse/pull/25165) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)). Added an ability to execute more merges and mutations than the number of threads in background pool. Merges and mutations will be executed step by step according to their sizes (lower is more prioritized). The ratio of the number of tasks to threads to execute is controlled by a setting `background_merges_mutations_concurrency_ratio`, 2 by default. [#29140](https://github.com/ClickHouse/ClickHouse/pull/29140) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow to use asynchronous reads for remote filesystems. Lower the number of seeks while reading from remote filesystems. It improves performance tremendously and makes the experimental `web` and `s3` disks to work faster than EBS under certain conditions. [#29205](https://github.com/ClickHouse/ClickHouse/pull/29205) ([Kseniia Sumarokova](https://github.com/kssenii)). In the meantime, the `web` disk type (static dataset hosted on a web server) is graduated from being experimental to be production ready.
* Queries with `INTO OUTFILE` in `clickhouse-client` will use multiple threads. Fix the issue with flickering progress-bar when using `INTO OUTFILE`. This closes [#30873](https://github.com/ClickHouse/ClickHouse/issues/30873). This closes [#30872](https://github.com/ClickHouse/ClickHouse/issues/30872). [#30886](https://github.com/ClickHouse/ClickHouse/pull/30886) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Reduce amount of redundant compressed data read from disk for some types `SELECT` queries (only for `MergeTree` engines family). [#30111](https://github.com/ClickHouse/ClickHouse/pull/30111) ([alesapin](https://github.com/alesapin)).
* Remove some redundant `seek` calls while reading compressed blocks in MergeTree table engines family. [#29766](https://github.com/ClickHouse/ClickHouse/pull/29766) ([alesapin](https://github.com/alesapin)).
* Make `url` table function to process multiple URLs in parallel. This closes [#29670](https://github.com/ClickHouse/ClickHouse/issues/29670) and closes [#29671](https://github.com/ClickHouse/ClickHouse/issues/29671). [#29673](https://github.com/ClickHouse/ClickHouse/pull/29673) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve performance of aggregation in order of primary key (with enabled setting `optimize_aggregation_in_order`). [#30266](https://github.com/ClickHouse/ClickHouse/pull/30266) ([Anton Popov](https://github.com/CurtizJ)).
* Now clickhouse is using DNS cache while communicating with external S3. [#29999](https://github.com/ClickHouse/ClickHouse/pull/29999) ([alesapin](https://github.com/alesapin)).
* Add support for pushdown of `IS NULL`/`IS NOT NULL` to external databases (i.e. MySQL). [#29463](https://github.com/ClickHouse/ClickHouse/pull/29463) ([Azat Khuzhin](https://github.com/azat)). Transform `isNull`/`isNotNull` to `IS NULL`/`IS NOT NULL` (for external dbs, i.e. MySQL). [#29446](https://github.com/ClickHouse/ClickHouse/pull/29446) ([Azat Khuzhin](https://github.com/azat)).
* SELECT queries from Dictionary tables will use multiple threads. [#30500](https://github.com/ClickHouse/ClickHouse/pull/30500) ([Maksim Kita](https://github.com/kitaisreal)).
* Improve performance for filtering (WHERE operation) of `Decimal` columns. [#30431](https://github.com/ClickHouse/ClickHouse/pull/30431) ([Jun Jin](https://github.com/vesslanjin)).
* Remove branchy code in filter operation with a better implementation with popcnt/ctz which have better performance. [#29881](https://github.com/ClickHouse/ClickHouse/pull/29881) ([Jun Jin](https://github.com/vesslanjin)).
* Improve filter bytemask generator (used for WHERE operator) function all in one with SSE/AVX2/AVX512 instructions. Note that by default ClickHouse is only using SSE, so it's only relevant for custom builds. [#30014](https://github.com/ClickHouse/ClickHouse/pull/30014) ([jasperzhu](https://github.com/jinjunzh)). [#30670](https://github.com/ClickHouse/ClickHouse/pull/30670) ([jasperzhu](https://github.com/jinjunzh)).
* Improve the performance of SUM aggregate function of Nullable floating point numbers. [#28906](https://github.com/ClickHouse/ClickHouse/pull/28906) ([Raúl Marín](https://github.com/Algunenano)).
* Speed up part loading process with multiple disks are in use. The idea is similar to https://github.com/ClickHouse/ClickHouse/pull/16423 . Prod env shows improvement: 24 min -> 16 min . [#28363](https://github.com/ClickHouse/ClickHouse/pull/28363) ([Amos Bird](https://github.com/amosbird)).
* Reduce default settings for S3 multipart upload part size to lower memory usage. [#28679](https://github.com/ClickHouse/ClickHouse/pull/28679) ([ianton-ru](https://github.com/ianton-ru)).
* Speed up `bitmapAnd` function. [#28332](https://github.com/ClickHouse/ClickHouse/pull/28332) ([dddounaiking](https://github.com/OodounaikingoO)).
* Removed sub-optimal mutation notifications in `StorageMergeTree` when merges are still going. [#27552](https://github.com/ClickHouse/ClickHouse/pull/27552) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Attempt to improve performance of string comparison. [#28767](https://github.com/ClickHouse/ClickHouse/pull/28767) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Primary key index and partition filter can work in tuple. [#29281](https://github.com/ClickHouse/ClickHouse/pull/29281) ([凌涛](https://github.com/lingtaolf)).
* If query has multiple quantile aggregate functions with the same arguments but different level parameter, they will be fused together and executed in one pass if the setting `optimize_syntax_fuse_functions` is enabled. [#26657](https://github.com/ClickHouse/ClickHouse/pull/26657) ([hexiaoting](https://github.com/hexiaoting)).
* Now min-max aggregation over the first expression of primary key is optimized by projection. This is for [#329](https://github.com/ClickHouse/ClickHouse/issues/329). [#29918](https://github.com/ClickHouse/ClickHouse/pull/29918) ([Amos Bird](https://github.com/amosbird)).
#### Experimental Feature
* Add ability to change nodes configuration (in `.xml` file) for ClickHouse Keeper. [#30372](https://github.com/ClickHouse/ClickHouse/pull/30372) ([alesapin](https://github.com/alesapin)).
* Add `sparkbar` aggregate function. This closes [#26175](https://github.com/ClickHouse/ClickHouse/issues/26175). [#27481](https://github.com/ClickHouse/ClickHouse/pull/27481) ([小路](https://github.com/nicelulu)). Note: there is one flaw in this function, the behaviour will be changed in future releases.
#### Improvement
* Allow user to change log levels without restart. [#29586](https://github.com/ClickHouse/ClickHouse/pull/29586) ([Nikolay Degterinsky](https://github.com/evillique)).
* Multiple improvements for SQL UDF. Queries for manipulation of SQL User Defined Functions now support ON CLUSTER clause. Example `CREATE FUNCTION test_function ON CLUSTER 'cluster' AS x -> x + 1;`. Closes [#30666](https://github.com/ClickHouse/ClickHouse/issues/30666). [#30734](https://github.com/ClickHouse/ClickHouse/pull/30734) ([Maksim Kita](https://github.com/kitaisreal)). Support `CREATE OR REPLACE`, `CREATE IF NOT EXISTS` syntaxes. [#30454](https://github.com/ClickHouse/ClickHouse/pull/30454) ([Maksim Kita](https://github.com/kitaisreal)). Added DROP IF EXISTS support. Example `DROP FUNCTION IF EXISTS test_function`. [#30437](https://github.com/ClickHouse/ClickHouse/pull/30437) ([Maksim Kita](https://github.com/kitaisreal)). Support lambdas. Example `CREATE FUNCTION lambda_function AS x -> arrayMap(element -> element * 2, x);`. [#30435](https://github.com/ClickHouse/ClickHouse/pull/30435) ([Maksim Kita](https://github.com/kitaisreal)). Support SQL user defined functions for `clickhouse-local`. [#30179](https://github.com/ClickHouse/ClickHouse/pull/30179) ([Maksim Kita](https://github.com/kitaisreal)).
* Enable per-query memory profiler (set to `memory_profiler_step` = 4MiB) globally. [#29455](https://github.com/ClickHouse/ClickHouse/pull/29455) ([Azat Khuzhin](https://github.com/azat)).
* Added columns `data_compressed_bytes`, `data_uncompressed_bytes`, `marks_bytes` into `system.data_skipping_indices`. Added columns `secondary_indices_compressed_bytes`, `secondary_indices_uncompressed_bytes`, `secondary_indices_marks_bytes` into `system.parts`. Closes [#29697](https://github.com/ClickHouse/ClickHouse/issues/29697). [#29896](https://github.com/ClickHouse/ClickHouse/pull/29896) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `table` alias to system.tables and `database` alias to system.databases [#29677](https://github.com/ClickHouse/ClickHouse/issues/29677). [#29882](https://github.com/ClickHouse/ClickHouse/pull/29882) ([kevin wan](https://github.com/MaxWk)).
* Correctly resolve interdependencies between tables on server startup. Closes [#8004](https://github.com/ClickHouse/ClickHouse/issues/8004), closes [#15170](https://github.com/ClickHouse/ClickHouse/issues/15170). [#28373](https://github.com/ClickHouse/ClickHouse/pull/28373) ([tavplubix](https://github.com/tavplubix)).
* Avoid error "Division by zero" when denominator is Nullable in functions `divide`, `intDiv` and `modulo`. Closes [#22621](https://github.com/ClickHouse/ClickHouse/issues/22621). [#28352](https://github.com/ClickHouse/ClickHouse/pull/28352) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow to parse values of `Date` data type in text formats as `YYYYMMDD` in addition to `YYYY-MM-DD`. This closes [#30870](https://github.com/ClickHouse/ClickHouse/issues/30870). [#30871](https://github.com/ClickHouse/ClickHouse/pull/30871) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Web UI: render bars in table cells. [#29792](https://github.com/ClickHouse/ClickHouse/pull/29792) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* User can now create dictionaries with comments: `CREATE DICTIONARY ... COMMENT 'vaue'` ... [#29899](https://github.com/ClickHouse/ClickHouse/pull/29899) ([Vasily Nemkov](https://github.com/Enmk)). Users now can set comments to database in `CREATE DATABASE` statement ... [#29429](https://github.com/ClickHouse/ClickHouse/pull/29429) ([Vasily Nemkov](https://github.com/Enmk)).
* Introduce `compiled_expression_cache_elements_size` setting. If you will ever want to use this setting, you will already know what it does. [#30667](https://github.com/ClickHouse/ClickHouse/pull/30667) ([Maksim Kita](https://github.com/kitaisreal)).
* clickhouse-format now supports option `--query`. In previous versions you have to pass the query to stdin. [#29325](https://github.com/ClickHouse/ClickHouse/pull/29325) ([凌涛](https://github.com/lingtaolf)).
* Support `ALTER TABLE` for tables in `Memory` databases. Memory databases are used in `clickhouse-local`. [#30866](https://github.com/ClickHouse/ClickHouse/pull/30866) ([tavplubix](https://github.com/tavplubix)).
* Arrays of all serializable types are now supported by `arrayStringConcat`. [#30840](https://github.com/ClickHouse/ClickHouse/pull/30840) ([Nickita Taranov](https://github.com/nickitat)).
* ClickHouse now will account docker/cgroups limitations to get system memory amount. See [#25662](https://github.com/ClickHouse/ClickHouse/issues/25662). [#30574](https://github.com/ClickHouse/ClickHouse/pull/30574) ([Pavel Medvedev](https://github.com/pmed)).
* Fetched table structure for PostgreSQL database is more reliable now. [#30477](https://github.com/ClickHouse/ClickHouse/pull/30477) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Full support of positional arguments in GROUP BY and ORDER BY. [#30433](https://github.com/ClickHouse/ClickHouse/pull/30433) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Allow extracting non-string element as string using JSONExtractString. This is for [pull/25452#issuecomment-927123287](https://github.com/ClickHouse/ClickHouse/pull/25452#issuecomment-927123287). [#30426](https://github.com/ClickHouse/ClickHouse/pull/30426) ([Amos Bird](https://github.com/amosbird)).
* Added an ability to use FINAL clause in SELECT queries from `GraphiteMergeTree`. [#30360](https://github.com/ClickHouse/ClickHouse/pull/30360) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Minor improvements in replica cloning and enqueuing fetch for broken parts, that should avoid extremely rare hanging of `GET_PART` entries in replication queue. [#30346](https://github.com/ClickHouse/ClickHouse/pull/30346) ([tavplubix](https://github.com/tavplubix)).
* Allow symlinks to files in `user_files` directory for file table function. [#30309](https://github.com/ClickHouse/ClickHouse/pull/30309) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fixed comparison of `Date32` with `Date`, `DateTime`, `DateTime64` and `String`. [#30219](https://github.com/ClickHouse/ClickHouse/pull/30219) ([liang.huang](https://github.com/lhuang09287750)).
* Allow to remove `SAMPLE BY` expression from `MergeTree` tables (`ALTER TABLE <table> REMOVE SAMPLE BY`). [#30180](https://github.com/ClickHouse/ClickHouse/pull/30180) ([Anton Popov](https://github.com/CurtizJ)).
* Now `Keeper` (as part of `clickhouse-server`) will start asynchronously if it can connect to some other node. [#30170](https://github.com/ClickHouse/ClickHouse/pull/30170) ([alesapin](https://github.com/alesapin)).
* Now `clickhouse-client` supports native multi-line editing. [#30143](https://github.com/ClickHouse/ClickHouse/pull/30143) ([Amos Bird](https://github.com/amosbird)).
* `polygon` dictionaries (reverse geocoding): added support for reading the dictionary content with SELECT query method if setting `store_polygon_key_column` = true. Closes [#30090](https://github.com/ClickHouse/ClickHouse/issues/30090). [#30142](https://github.com/ClickHouse/ClickHouse/pull/30142) ([Maksim Kita](https://github.com/kitaisreal)).
* Add ClickHouse logo to Play UI. [#29674](https://github.com/ClickHouse/ClickHouse/pull/29674) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Better exception message while reading column from Arrow-supported formats like `Arrow`, `ArrowStream`, `Parquet` and `ORC`. This closes [#29926](https://github.com/ClickHouse/ClickHouse/issues/29926). [#29927](https://github.com/ClickHouse/ClickHouse/pull/29927) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix data-race between flush and startup in `Buffer` tables. This can appear in tests. [#29930](https://github.com/ClickHouse/ClickHouse/pull/29930) ([Azat Khuzhin](https://github.com/azat)).
* Fix `lock-order-inversion` between `DROP TABLE` for `DatabaseMemory` and `LiveView`. Live View is an experimental feature. Memory database is used in clickhouse-local. [#29929](https://github.com/ClickHouse/ClickHouse/pull/29929) ([Azat Khuzhin](https://github.com/azat)).
* Fix lock-order-inversion between periodic dictionary reload and config reload. [#29928](https://github.com/ClickHouse/ClickHouse/pull/29928) ([Azat Khuzhin](https://github.com/azat)).
* Update zoneinfo files to 2021c. [#29925](https://github.com/ClickHouse/ClickHouse/pull/29925) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add ability to configure retries and delays between them for `clickhouse-copier`. [#29921](https://github.com/ClickHouse/ClickHouse/pull/29921) ([Azat Khuzhin](https://github.com/azat)).
* Add `shutdown_wait_unfinished_queries` server setting to allowing waiting for running queries up to `shutdown_wait_unfinished` time. This is for [#24451](https://github.com/ClickHouse/ClickHouse/issues/24451). [#29914](https://github.com/ClickHouse/ClickHouse/pull/29914) ([Amos Bird](https://github.com/amosbird)).
* Add ability to trace peak memory usage (with new trace_type in `system.trace_log` - `MemoryPeak`). [#29858](https://github.com/ClickHouse/ClickHouse/pull/29858) ([Azat Khuzhin](https://github.com/azat)).
* PostgreSQL foreign tables: Added partitioned table prefix 'p' for the query for fetching replica identity index. [#29828](https://github.com/ClickHouse/ClickHouse/pull/29828) ([Shoh Jahon](https://github.com/Shohjahon)).
* Apply `max_untracked_memory`/`memory_profiler_step`/`memory_profiler_sample_probability` during mutate/merge to profile memory usage during merges. [#29681](https://github.com/ClickHouse/ClickHouse/pull/29681) ([Azat Khuzhin](https://github.com/azat)).
* Query obfuscator: `clickhouse-format --obfuscate` now works with more types of queries. [#29672](https://github.com/ClickHouse/ClickHouse/pull/29672) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the issue: `clickhouse-format --obfuscate` cannot process queries with embedded dictionaries (functions `regionTo...`). [#29667](https://github.com/ClickHouse/ClickHouse/pull/29667) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix incorrect Nullable processing of JSON functions. This fixes [#29615](https://github.com/ClickHouse/ClickHouse/issues/29615) . Mark as improvement because https://github.com/ClickHouse/ClickHouse/pull/28012 is not released. [#29659](https://github.com/ClickHouse/ClickHouse/pull/29659) ([Amos Bird](https://github.com/amosbird)).
* Increase `listen_backlog` by default (to match default in newer linux kernel). [#29643](https://github.com/ClickHouse/ClickHouse/pull/29643) ([Azat Khuzhin](https://github.com/azat)).
* Reload dictionaries, models, user defined executable functions if servers config `dictionaries_config`, `models_config`, `user_defined_executable_functions_config` changes. Closes [#28142](https://github.com/ClickHouse/ClickHouse/issues/28142). [#29529](https://github.com/ClickHouse/ClickHouse/pull/29529) ([Maksim Kita](https://github.com/kitaisreal)).
* Get rid of pointless restriction on projection name. Now projection name can start with `tmp_`. [#29520](https://github.com/ClickHouse/ClickHouse/pull/29520) ([Amos Bird](https://github.com/amosbird)).
* Fixed `There is no query or query context has expired` error in mutations with nested subqueries. Do not allow subqueries in mutation if table is replicated and `allow_nondeterministic_mutations` setting is disabled. [#29495](https://github.com/ClickHouse/ClickHouse/pull/29495) ([tavplubix](https://github.com/tavplubix)).
* Apply config changes to `max_concurrent_queries` during runtime (no need to restart). [#29414](https://github.com/ClickHouse/ClickHouse/pull/29414) ([Raúl Marín](https://github.com/Algunenano)).
* Added setting `use_skip_indexes`. [#29405](https://github.com/ClickHouse/ClickHouse/pull/29405) ([Maksim Kita](https://github.com/kitaisreal)).
* Add support for `FREEZE`ing in-memory parts (for backups). [#29376](https://github.com/ClickHouse/ClickHouse/pull/29376) ([Mo Xuan](https://github.com/mo-avatar)).
* Pass through initial query_id for `clickhouse-benchmark` (previously if you run remote query via `clickhouse-benchmark`, queries on shards will not be linked to the initial query via `initial_query_id`). [#29364](https://github.com/ClickHouse/ClickHouse/pull/29364) ([Azat Khuzhin](https://github.com/azat)).
* Skip indexes `tokenbf_v1` and `ngrambf_v1`: added support for `Array` data type with key of `String` of `FixedString` type. [#29280](https://github.com/ClickHouse/ClickHouse/pull/29280) ([Maksim Kita](https://github.com/kitaisreal)). Skip indexes `tokenbf_v1` and `ngrambf_v1` added support for `Map` data type with key of `String` of `FixedString` type. Author @lingtaolf. [#29220](https://github.com/ClickHouse/ClickHouse/pull/29220) ([Maksim Kita](https://github.com/kitaisreal)).
* Function `has`: added support for `Map` data type. [#29267](https://github.com/ClickHouse/ClickHouse/pull/29267) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `compress_logs` settings for clickhouse-keeper which allow to compress clickhouse-keeper logs (for replicated state machine) in `ZSTD` . Implements: [#26977](https://github.com/ClickHouse/ClickHouse/issues/26977). [#29223](https://github.com/ClickHouse/ClickHouse/pull/29223) ([alesapin](https://github.com/alesapin)).
* Add a setting `external_table_strict_query` - it will force passing the whole WHERE expression in queries to foreign databases even if it is incompatible. [#29206](https://github.com/ClickHouse/ClickHouse/pull/29206) ([Azat Khuzhin](https://github.com/azat)).
* Disable projections when `ARRAY JOIN` is used. In previous versions projection analysis may break aliases in array join. [#29139](https://github.com/ClickHouse/ClickHouse/pull/29139) ([Amos Bird](https://github.com/amosbird)).
* Support more types in `MsgPack` input/output format. [#29077](https://github.com/ClickHouse/ClickHouse/pull/29077) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow to input and output `LowCardinality` columns in `ORC` input/output format. [#29062](https://github.com/ClickHouse/ClickHouse/pull/29062) ([Kruglov Pavel](https://github.com/Avogar)).
* Select from `system.distributed_ddl_queue` might show incorrect values, it's fixed. [#29061](https://github.com/ClickHouse/ClickHouse/pull/29061) ([tavplubix](https://github.com/tavplubix)).
* Correct behaviour with unknown methods for HTTP connection. Solves [#29050](https://github.com/ClickHouse/ClickHouse/issues/29050). [#29057](https://github.com/ClickHouse/ClickHouse/pull/29057) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* `clickhouse-keeper`: Fix bug in `clickhouse-keeper-converter` which can lead to some data loss while restoring from ZooKeeper logs (not snapshot). [#29030](https://github.com/ClickHouse/ClickHouse/pull/29030) ([小路](https://github.com/nicelulu)). Fix bug in `clickhouse-keeper-converter` which can lead to incorrect ZooKeeper log deserialization. [#29071](https://github.com/ClickHouse/ClickHouse/pull/29071) ([小路](https://github.com/nicelulu)).
* Apply settings from `CREATE ... AS SELECT` queries (fixes: [#28810](https://github.com/ClickHouse/ClickHouse/issues/28810)). [#28962](https://github.com/ClickHouse/ClickHouse/pull/28962) ([Azat Khuzhin](https://github.com/azat)).
* Respect default database setting for ALTER TABLE ... ON CLUSTER ... REPLACE/MOVE PARTITION FROM/TO ... [#28955](https://github.com/ClickHouse/ClickHouse/pull/28955) ([anneji-dev](https://github.com/anneji-dev)).
* gRPC protocol: Allow change server-side compression from client. [#28953](https://github.com/ClickHouse/ClickHouse/pull/28953) ([Vitaly Baranov](https://github.com/vitlibar)).
* Skip "no data" exception when reading thermal sensors for asynchronous metrics. This closes [#28852](https://github.com/ClickHouse/ClickHouse/issues/28852). [#28882](https://github.com/ClickHouse/ClickHouse/pull/28882) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed logical race condition that might cause `Dictionary not found` error for existing dictionary in rare cases. [#28853](https://github.com/ClickHouse/ClickHouse/pull/28853) ([tavplubix](https://github.com/tavplubix)).
* Relax nested function for If-combinator check (but forbid nested identical combinators). [#28828](https://github.com/ClickHouse/ClickHouse/pull/28828) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible uncaught exception during server termination. [#28761](https://github.com/ClickHouse/ClickHouse/pull/28761) ([Azat Khuzhin](https://github.com/azat)).
* Forbid cleaning of tmp directories that can be used by an active mutation/merge if mutation/merge is extraordinarily long. [#28760](https://github.com/ClickHouse/ClickHouse/pull/28760) ([Azat Khuzhin](https://github.com/azat)).
* Allow optimization `optimize_arithmetic_operations_in_aggregate_functions = 1` when alias is used. [#28746](https://github.com/ClickHouse/ClickHouse/pull/28746) ([Amos Bird](https://github.com/amosbird)).
* Implement `detach_not_byte_identical_parts` setting for `ReplicatedMergeTree`, that will detach instead of remove not byte-identical parts (after mege/mutate). [#28708](https://github.com/ClickHouse/ClickHouse/pull/28708) ([Azat Khuzhin](https://github.com/azat)).
* Implement `max_suspicious_broken_parts_bytes` setting for `MergeTree` (to limit total size of all broken parts, default is `1GiB`). [#28707](https://github.com/ClickHouse/ClickHouse/pull/28707) ([Azat Khuzhin](https://github.com/azat)).
* Enable expanding macros in `RabbitMQ` table settings. [#28683](https://github.com/ClickHouse/ClickHouse/pull/28683) ([Vitaly Baranov](https://github.com/vitlibar)).
* Restore the possibility to read data of a table using the `Log` engine in multiple threads. [#28125](https://github.com/ClickHouse/ClickHouse/pull/28125) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix misbehavior of NULL column handling in JSON functions. This fixes [#27930](https://github.com/ClickHouse/ClickHouse/issues/27930). [#28012](https://github.com/ClickHouse/ClickHouse/pull/28012) ([Amos Bird](https://github.com/amosbird)).
* Allow to set the size of Mark/Uncompressed cache for skip indices separately from columns. [#27961](https://github.com/ClickHouse/ClickHouse/pull/27961) ([Amos Bird](https://github.com/amosbird)).
* Allow to mix JOIN with `USING` with other JOIN types. [#23881](https://github.com/ClickHouse/ClickHouse/pull/23881) ([darkkeks](https://github.com/darkkeks)).
* Update aws-sdk submodule for throttling in Yandex Cloud S3. [#30646](https://github.com/ClickHouse/ClickHouse/pull/30646) ([ianton-ru](https://github.com/ianton-ru)).
* Fix releasing query ID and session ID at the end of query processing while handing gRPC call. [#29954](https://github.com/ClickHouse/ClickHouse/pull/29954) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix shutdown of `AccessControlManager` to fix flaky test. [#29951](https://github.com/ClickHouse/ClickHouse/pull/29951) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix failed assertion in reading from `HDFS`. Update libhdfs3 library to be able to run in tests in debug. Closes [#29251](https://github.com/ClickHouse/ClickHouse/issues/29251). Closes [#27814](https://github.com/ClickHouse/ClickHouse/issues/27814). [#29276](https://github.com/ClickHouse/ClickHouse/pull/29276) ([Kseniia Sumarokova](https://github.com/kssenii)).
#### Build/Testing/Packaging Improvement
* Add support for FreeBSD builds for Aarch64 machines. [#29952](https://github.com/ClickHouse/ClickHouse/pull/29952) ([MikaelUrankar](https://github.com/MikaelUrankar)).
* Recursive submodules are no longer needed for ClickHouse. [#30315](https://github.com/ClickHouse/ClickHouse/pull/30315) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* ClickHouse can be statically built with Musl. This is added as experiment, it does not support building `odbc-bridge`, `library-bridge`, integration with CatBoost and some libraries. [#30248](https://github.com/ClickHouse/ClickHouse/pull/30248) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Enable `Protobuf`, `Arrow`, `ORC`, `Parquet` for `AArch64` and `Darwin` (macOS) builds. This closes [#29248](https://github.com/ClickHouse/ClickHouse/issues/29248). This closes [#28018](https://github.com/ClickHouse/ClickHouse/issues/28018). [#30015](https://github.com/ClickHouse/ClickHouse/pull/30015) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add cross-build for PowerPC (powerpc64le). This closes [#9589](https://github.com/ClickHouse/ClickHouse/issues/9589). Enable support for interaction with MySQL for AArch64 and PowerPC. This closes [#26301](https://github.com/ClickHouse/ClickHouse/issues/26301). [#30010](https://github.com/ClickHouse/ClickHouse/pull/30010) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs). [#29974](https://github.com/ClickHouse/ClickHouse/pull/29974) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Implemented structure-aware fuzzing approach in ClickHouse for select statement parser. [#30012](https://github.com/ClickHouse/ClickHouse/pull/30012) ([Paul](https://github.com/PaulCher)).
* Turning on experimental constexpr expressions evaluator for clang to speed up template code compilation. [#29668](https://github.com/ClickHouse/ClickHouse/pull/29668) ([myrrc](https://github.com/myrrc)).
* Add ability to compile using newer version fo glibc without using new symbols. [#29594](https://github.com/ClickHouse/ClickHouse/pull/29594) ([Azat Khuzhin](https://github.com/azat)).
* Reduce Debug build binary size by clang optimization option. [#28736](https://github.com/ClickHouse/ClickHouse/pull/28736) ([flynn](https://github.com/ucasfl)).
* Now all images for CI will be placed in the separate dockerhub repo. [#28656](https://github.com/ClickHouse/ClickHouse/pull/28656) ([alesapin](https://github.com/alesapin)).
* Improve support for build with clang-13. [#28046](https://github.com/ClickHouse/ClickHouse/pull/28046) ([Sergei Semin](https://github.com/syominsergey)).
* Add ability to print raw profile events to `clickhouse-client` (This can be useful for debugging and for testing). [#30064](https://github.com/ClickHouse/ClickHouse/pull/30064) ([Azat Khuzhin](https://github.com/azat)).
* Add time dependency for clickhouse-server unit (systemd and sysvinit init). [#28891](https://github.com/ClickHouse/ClickHouse/pull/28891) ([Azat Khuzhin](https://github.com/azat)).
* Reload stacktrace cache when symbol is reloaded. [#28137](https://github.com/ClickHouse/ClickHouse/pull/28137) ([Amos Bird](https://github.com/amosbird)).
#### Bug Fix
* Functions for case-insensitive search in UTF-8 strings like `positionCaseInsensitiveUTF8` and `countSubstringsCaseInsensitiveUTF8` might find substrings that actually does not match in very rare cases, it's fixed. [#30663](https://github.com/ClickHouse/ClickHouse/pull/30663) ([tavplubix](https://github.com/tavplubix)).
* Fix reading from empty file on encrypted disk. [#30494](https://github.com/ClickHouse/ClickHouse/pull/30494) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix transformation of disjunctions chain to `IN` (controlled by settings `optimize_min_equality_disjunction_chain_length`) in distributed queries with settings `legacy_column_name_of_tuple_literal = 0`. [#28658](https://github.com/ClickHouse/ClickHouse/pull/28658) ([Anton Popov](https://github.com/CurtizJ)).
* Allow using a materialized column as the sharding key in a distributed table even if `insert_allow_materialized_columns=0`:. [#28637](https://github.com/ClickHouse/ClickHouse/pull/28637) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix `ORDER BY ... WITH FILL` with set `TO` and `FROM` and no rows in result set. [#30888](https://github.com/ClickHouse/ClickHouse/pull/30888) ([Anton Popov](https://github.com/CurtizJ)).
* Fix set index not used in AND/OR expressions when there are more than two operands. This fixes [#30416](https://github.com/ClickHouse/ClickHouse/issues/30416) . [#30887](https://github.com/ClickHouse/ClickHouse/pull/30887) ([Amos Bird](https://github.com/amosbird)).
* Fix crash when projection with hashing function is materialized. This fixes [#30861](https://github.com/ClickHouse/ClickHouse/issues/30861) . The issue is similar to https://github.com/ClickHouse/ClickHouse/pull/28560 which is a lack of proper understanding of the invariant of header's emptyness. [#30877](https://github.com/ClickHouse/ClickHouse/pull/30877) ([Amos Bird](https://github.com/amosbird)).
* Fixed ambiguity when extracting auxiliary ZooKeeper name from ZooKeeper path in `ReplicatedMergeTree`. Previously server might fail to start with `Unknown auxiliary ZooKeeper name` if ZooKeeper path contains a colon. Fixes [#29052](https://github.com/ClickHouse/ClickHouse/issues/29052). Also it was allowed to specify ZooKeeper path that does not start with slash, but now it's deprecated and creation of new tables with such path is not allowed. Slashes and colons in auxiliary ZooKeeper names are not allowed too. [#30822](https://github.com/ClickHouse/ClickHouse/pull/30822) ([tavplubix](https://github.com/tavplubix)).
* Clean temporary directory when localBackup failed by some reason. [#30797](https://github.com/ClickHouse/ClickHouse/pull/30797) ([ianton-ru](https://github.com/ianton-ru)).
* Fixed a race condition between `REPLACE/MOVE PARTITION` and background merge in non-replicated `MergeTree` that might cause a part of moved/replaced data to remain in partition. Fixes [#29327](https://github.com/ClickHouse/ClickHouse/issues/29327). [#30717](https://github.com/ClickHouse/ClickHouse/pull/30717) ([tavplubix](https://github.com/tavplubix)).
* Fix PREWHERE with WHERE in case of always true PREWHERE. [#30668](https://github.com/ClickHouse/ClickHouse/pull/30668) ([Azat Khuzhin](https://github.com/azat)).
* Limit push down optimization could cause a error `Cannot find column`. Fixes [#30438](https://github.com/ClickHouse/ClickHouse/issues/30438). [#30562](https://github.com/ClickHouse/ClickHouse/pull/30562) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Add missing parenthesis for `isNotNull`/`isNull` rewrites to `IS [NOT] NULL` (fixes queries that has something like `isNotNull(1)+isNotNull(2)`). [#30520](https://github.com/ClickHouse/ClickHouse/pull/30520) ([Azat Khuzhin](https://github.com/azat)).
* Fix deadlock on ALTER with scalar subquery to the same table, close [#30461](https://github.com/ClickHouse/ClickHouse/issues/30461). [#30492](https://github.com/ClickHouse/ClickHouse/pull/30492) ([Vladimir C](https://github.com/vdimir)).
* Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. [#30432](https://github.com/ClickHouse/ClickHouse/pull/30432) ([tavplubix](https://github.com/tavplubix)).
* Queries with condition like `IN (subquery)` could return incorrect result in case if aggregate projection applied. Fixed creation of sets for projections. [#30310](https://github.com/ClickHouse/ClickHouse/pull/30310) ([Amos Bird](https://github.com/amosbird)).
* Fix column alias resolution of JOIN queries when projection is enabled. This fixes [#30146](https://github.com/ClickHouse/ClickHouse/issues/30146). [#30293](https://github.com/ClickHouse/ClickHouse/pull/30293) ([Amos Bird](https://github.com/amosbird)).
* Fix some deficiency in `replaceRegexpAll` function. [#30292](https://github.com/ClickHouse/ClickHouse/pull/30292) ([Memo](https://github.com/Joeywzr)).
* Fix ComplexKeyHashedDictionary, ComplexKeySparseHashedDictionary parsing `preallocate` option from layout config. [#30246](https://github.com/ClickHouse/ClickHouse/pull/30246) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix `[I]LIKE` function. Closes [#28661](https://github.com/ClickHouse/ClickHouse/issues/28661). [#30244](https://github.com/ClickHouse/ClickHouse/pull/30244) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix crash with shortcircuit and lowcardinality in multiIf. [#30243](https://github.com/ClickHouse/ClickHouse/pull/30243) ([Raúl Marín](https://github.com/Algunenano)).
* FlatDictionary, HashedDictionary fix bytes_allocated calculation for nullable attributes. [#30238](https://github.com/ClickHouse/ClickHouse/pull/30238) ([Maksim Kita](https://github.com/kitaisreal)).
* Allow identifiers starting with numbers in multiple joins. [#30230](https://github.com/ClickHouse/ClickHouse/pull/30230) ([Vladimir C](https://github.com/vdimir)).
* Fix reading from `MergeTree` with `max_read_buffer_size = 0` (when the user wants to shoot himself in the foot) (can lead to exceptions `Can't adjust last granule`, `LOGICAL_ERROR`, or even data loss). [#30192](https://github.com/ClickHouse/ClickHouse/pull/30192) ([Azat Khuzhin](https://github.com/azat)).
* Fix `pread_fake_async`/`pread_threadpool` with `min_bytes_to_use_direct_io`. [#30191](https://github.com/ClickHouse/ClickHouse/pull/30191) ([Azat Khuzhin](https://github.com/azat)).
* Fix INSERT SELECT incorrectly fills MATERIALIZED column based of Nullable column. [#30189](https://github.com/ClickHouse/ClickHouse/pull/30189) ([Azat Khuzhin](https://github.com/azat)).
* Support nullable arguments in function `initializeAggregation`. [#30177](https://github.com/ClickHouse/ClickHouse/pull/30177) ([Anton Popov](https://github.com/CurtizJ)).
* Fix error `Port is already connected` for queries with `GLOBAL IN` and `WITH TOTALS`. Only for 21.9 and 21.10. [#30086](https://github.com/ClickHouse/ClickHouse/pull/30086) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix race between MOVE PARTITION and merges/mutations for MergeTree. [#30074](https://github.com/ClickHouse/ClickHouse/pull/30074) ([Azat Khuzhin](https://github.com/azat)).
* Dropped `Memory` database might reappear after server restart, it's fixed ([#29795](https://github.com/ClickHouse/ClickHouse/issues/29795)). Also added `force_remove_data_recursively_on_drop` setting as a workaround for `Directory not empty` error when dropping `Ordinary` database (because it's not possible to remove data leftovers manually in cloud environment). [#30054](https://github.com/ClickHouse/ClickHouse/pull/30054) ([tavplubix](https://github.com/tavplubix)).
* Fix crash of sample by `tuple()`, closes [#30004](https://github.com/ClickHouse/ClickHouse/issues/30004). [#30016](https://github.com/ClickHouse/ClickHouse/pull/30016) ([flynn](https://github.com/ucasfl)).
* try to close issue: [#29965](https://github.com/ClickHouse/ClickHouse/issues/29965). [#29976](https://github.com/ClickHouse/ClickHouse/pull/29976) ([hexiaoting](https://github.com/hexiaoting)).
* Fix possible data-race between `FileChecker` and `StorageLog`/`StorageStripeLog`. [#29959](https://github.com/ClickHouse/ClickHouse/pull/29959) ([Azat Khuzhin](https://github.com/azat)).
* Fix data-race between `LogSink::writeMarks()` and `LogSource` in `StorageLog`. [#29946](https://github.com/ClickHouse/ClickHouse/pull/29946) ([Azat Khuzhin](https://github.com/azat)).
* Fix potential resource leak of the concurrent query limit of merge tree tables introduced in https://github.com/ClickHouse/ClickHouse/pull/19544. [#29879](https://github.com/ClickHouse/ClickHouse/pull/29879) ([Amos Bird](https://github.com/amosbird)).
* Fix system tables recreation check (fails to detect changes in enum values). [#29857](https://github.com/ClickHouse/ClickHouse/pull/29857) ([Azat Khuzhin](https://github.com/azat)).
* MaterializedMySQL: Fix an issue where if the connection to MySQL was lost, only parts of a transaction could be processed. [#29837](https://github.com/ClickHouse/ClickHouse/pull/29837) ([Håvard Kvålen](https://github.com/havardk)).
* Avoid `Timeout exceeded: elapsed 18446744073.709553 seconds` error that might happen in extremely rare cases, presumably due to some bug in kernel. Fixes [#29154](https://github.com/ClickHouse/ClickHouse/issues/29154). [#29811](https://github.com/ClickHouse/ClickHouse/pull/29811) ([tavplubix](https://github.com/tavplubix)).
* Fix bad cast in `ATTACH TABLE ... FROM 'path'` query when non-string literal is used instead of path. It may lead to reading of uninitialized memory. [#29790](https://github.com/ClickHouse/ClickHouse/pull/29790) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix concurrent access to `LowCardinality` during `GROUP BY` (in combination with `Buffer` tables it may lead to troubles). [#29782](https://github.com/ClickHouse/ClickHouse/pull/29782) ([Azat Khuzhin](https://github.com/azat)).
* Fix incorrect `GROUP BY` (multiple rows with the same keys in result) in case of distributed query when shards had mixed versions `<= 21.3` and `>= 21.4`, `GROUP BY` key had several columns all with fixed size, and two-level aggregation was activated (see `group_by_two_level_threshold` and `group_by_two_level_threshold_bytes`). Fixes [#29580](https://github.com/ClickHouse/ClickHouse/issues/29580). [#29735](https://github.com/ClickHouse/ClickHouse/pull/29735) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed incorrect behaviour of setting `materialized_postgresql_tables_list` at server restart. Found in [#28529](https://github.com/ClickHouse/ClickHouse/issues/28529). [#29686](https://github.com/ClickHouse/ClickHouse/pull/29686) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Condition in filter predicate could be lost after push-down optimisation. [#29625](https://github.com/ClickHouse/ClickHouse/pull/29625) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix JIT expression compilation with aliases and short-circuit expression evaluation. Closes [#29403](https://github.com/ClickHouse/ClickHouse/issues/29403). [#29574](https://github.com/ClickHouse/ClickHouse/pull/29574) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix rare segfault in `ALTER MODIFY` query when using incorrect table identifier in `DEFAULT` expression like `x.y.z...` Fixes [#29184](https://github.com/ClickHouse/ClickHouse/issues/29184). [#29573](https://github.com/ClickHouse/ClickHouse/pull/29573) ([alesapin](https://github.com/alesapin)).
* Fix nullptr deference for `GROUP BY WITH TOTALS HAVING` (when the column from `HAVING` wasn't selected). [#29553](https://github.com/ClickHouse/ClickHouse/pull/29553) ([Azat Khuzhin](https://github.com/azat)).
* Avoid deadlocks when reading and writting on Join table engine tables at the same time. [#29544](https://github.com/ClickHouse/ClickHouse/pull/29544) ([Raúl Marín](https://github.com/Algunenano)).
* Fix bug in check `pathStartsWith` becuase there was bug with the usage of `std::mismatch`: ` The behavior is undefined if the second range is shorter than the first range.`. [#29531](https://github.com/ClickHouse/ClickHouse/pull/29531) ([Kseniia Sumarokova](https://github.com/kssenii)).
* In ODBC bridge add retries for error Invalid cursor state. It is a retriable error. Closes [#29473](https://github.com/ClickHouse/ClickHouse/issues/29473). [#29518](https://github.com/ClickHouse/ClickHouse/pull/29518) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fixed incorrect table name parsing on loading of `Lazy` database. Fixes [#29456](https://github.com/ClickHouse/ClickHouse/issues/29456). [#29476](https://github.com/ClickHouse/ClickHouse/pull/29476) ([tavplubix](https://github.com/tavplubix)).
* Fix possible `Block structure mismatch` for subqueries with pushed-down `HAVING` predicate. Fixes [#29010](https://github.com/ClickHouse/ClickHouse/issues/29010). [#29475](https://github.com/ClickHouse/ClickHouse/pull/29475) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix Logical error `Cannot capture columns` in functions greatest/least. Closes [#29334](https://github.com/ClickHouse/ClickHouse/issues/29334). [#29454](https://github.com/ClickHouse/ClickHouse/pull/29454) ([Kruglov Pavel](https://github.com/Avogar)).
* RocksDB table engine: fix race condition during multiple DB opening (and get back some tests that triggers the problem on CI). [#29393](https://github.com/ClickHouse/ClickHouse/pull/29393) ([Azat Khuzhin](https://github.com/azat)).
* Fix replicated access storage not shutting down cleanly when misconfigured. [#29388](https://github.com/ClickHouse/ClickHouse/pull/29388) ([Kevin Michel](https://github.com/kmichel-aiven)).
* Remove window function `nth_value` as it is not memory-safe. This closes [#29347](https://github.com/ClickHouse/ClickHouse/issues/29347). [#29348](https://github.com/ClickHouse/ClickHouse/pull/29348) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix vertical merges of projection parts. This fixes [#29253](https://github.com/ClickHouse/ClickHouse/issues/29253) . This PR also fixes several projection merge/mutation issues introduced in https://github.com/ClickHouse/ClickHouse/pull/25165. [#29337](https://github.com/ClickHouse/ClickHouse/pull/29337) ([Amos Bird](https://github.com/amosbird)).
* Fix hanging DDL queries on Replicated database while adding a new replica. [#29328](https://github.com/ClickHouse/ClickHouse/pull/29328) ([Kevin Michel](https://github.com/kmichel-aiven)).
* Fix connection timeouts (`send_timeout`/`receive_timeout`). [#29282](https://github.com/ClickHouse/ClickHouse/pull/29282) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible `Table columns structure in ZooKeeper is different from local table structure` exception while recreating or creating new replicas of `ReplicatedMergeTree`, when one of table columns have default expressions with case-insensitive functions. [#29266](https://github.com/ClickHouse/ClickHouse/pull/29266) ([Anton Popov](https://github.com/CurtizJ)).
* Send normal `Database doesn't exist error` (`UNKNOWN_DATABASE`) to the client (via TCP) instead of `Attempt to read after eof` (`ATTEMPT_TO_READ_AFTER_EOF`). [#29229](https://github.com/ClickHouse/ClickHouse/pull/29229) ([Azat Khuzhin](https://github.com/azat)).
* Fix segfault while inserting into column with type LowCardinality(Nullable) in Avro input format. [#29132](https://github.com/ClickHouse/ClickHouse/pull/29132) ([Kruglov Pavel](https://github.com/Avogar)).
* Do not allow to reuse previous credentials in case of inter-server secret (Before INSERT via Buffer/Kafka to Distributed table with interserver secret configured for that cluster, may re-use previously set user for that connection). [#29060](https://github.com/ClickHouse/ClickHouse/pull/29060) ([Azat Khuzhin](https://github.com/azat)).
* Handle `any_join_distinct_right_table_keys` when join with dictionary, close [#29007](https://github.com/ClickHouse/ClickHouse/issues/29007). [#29014](https://github.com/ClickHouse/ClickHouse/pull/29014) ([Vladimir C](https://github.com/vdimir)).
* Fix "Not found column ... in block" error, when join on alias column, close [#26980](https://github.com/ClickHouse/ClickHouse/issues/26980). [#29008](https://github.com/ClickHouse/ClickHouse/pull/29008) ([Vladimir C](https://github.com/vdimir)).
* Fix the number of threads used in `GLOBAL IN` subquery (it was executed in single threads since [#19414](https://github.com/ClickHouse/ClickHouse/issues/19414) bugfix). [#28997](https://github.com/ClickHouse/ClickHouse/pull/28997) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix bad optimizations of ORDER BY if it contains WITH FILL. This closes [#28908](https://github.com/ClickHouse/ClickHouse/issues/28908). This closes [#26049](https://github.com/ClickHouse/ClickHouse/issues/26049). [#28910](https://github.com/ClickHouse/ClickHouse/pull/28910) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix higher-order array functions (`SIGSEGV` for `arrayCompact`/`ILLEGAL_COLUMN` for `arrayDifference`/`arrayCumSumNonNegative`) with consts. [#28904](https://github.com/ClickHouse/ClickHouse/pull/28904) ([Azat Khuzhin](https://github.com/azat)).
* Fix waiting for mutation with `mutations_sync=2`. [#28889](https://github.com/ClickHouse/ClickHouse/pull/28889) ([Azat Khuzhin](https://github.com/azat)).
* Fix queries to external databases (i.e. MySQL) with multiple columns in IN ( i.e. `(k,v) IN ((1, 2))` ). [#28888](https://github.com/ClickHouse/ClickHouse/pull/28888) ([Azat Khuzhin](https://github.com/azat)).
* Fix bug with `LowCardinality` in short-curcuit function evaluation. Closes [#28884](https://github.com/ClickHouse/ClickHouse/issues/28884). [#28887](https://github.com/ClickHouse/ClickHouse/pull/28887) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix reading of subcolumns from compact parts. [#28873](https://github.com/ClickHouse/ClickHouse/pull/28873) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed a race condition between `DROP PART` and `REPLACE/MOVE PARTITION` that might cause replicas to diverge in rare cases. [#28864](https://github.com/ClickHouse/ClickHouse/pull/28864) ([tavplubix](https://github.com/tavplubix)).
* Fix expressions compilation with short circuit evaluation. [#28821](https://github.com/ClickHouse/ClickHouse/pull/28821) ([Azat Khuzhin](https://github.com/azat)).
* Fix extremely rare case when ReplicatedMergeTree replicas can diverge after hard reboot of all replicas. The error looks like `Part ... intersects (previous|next) part ...`. [#28817](https://github.com/ClickHouse/ClickHouse/pull/28817) ([alesapin](https://github.com/alesapin)).
* Better check for connection usability and also catch any exception in `RabbitMQ` shutdown just in case. [#28797](https://github.com/ClickHouse/ClickHouse/pull/28797) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix benign race condition in ReplicatedMergeTreeQueue. Shouldn't be visible for user, but can lead to subtle bugs. [#28734](https://github.com/ClickHouse/ClickHouse/pull/28734) ([alesapin](https://github.com/alesapin)).
* Fix possible crash for `SELECT` with partially created aggregate projection in case of exception. [#28700](https://github.com/ClickHouse/ClickHouse/pull/28700) ([Amos Bird](https://github.com/amosbird)).
* Fix the coredump in the creation of distributed tables, when the parameters passed in are wrong. [#28686](https://github.com/ClickHouse/ClickHouse/pull/28686) ([Zhiyong Wang](https://github.com/ljcui)).
* Add Settings.Names, Settings.Values aliases for system.processes table. [#28685](https://github.com/ClickHouse/ClickHouse/pull/28685) ([Vitaly](https://github.com/orloffv)).
* Support for S2 Geometry library: Fix the number of arguments required by `s2RectAdd` and `s2RectContains` functions. [#28663](https://github.com/ClickHouse/ClickHouse/pull/28663) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix invalid constant type conversion when Nullable or LowCardinality primary key is used. [#28636](https://github.com/ClickHouse/ClickHouse/pull/28636) ([Amos Bird](https://github.com/amosbird)).
* Fix "Column is not under aggregate function and not in GROUP BY" with PREWHERE (Fixes: [#28461](https://github.com/ClickHouse/ClickHouse/issues/28461)). [#28502](https://github.com/ClickHouse/ClickHouse/pull/28502) ([Azat Khuzhin](https://github.com/azat)).
### ClickHouse release v21.10, 2021-10-16
#### Backward Incompatible Change
* Now the following MergeTree table-level settings: `replicated_max_parallel_sends`, `replicated_max_parallel_sends_for_table`, `replicated_max_parallel_fetches`, `replicated_max_parallel_fetches_for_table` do nothing. They never worked well and were replaced with `max_replicated_fetches_network_bandwidth`, `max_replicated_sends_network_bandwidth` and `background_fetches_pool_size`. [#28404](https://github.com/ClickHouse/ClickHouse/pull/28404) ([alesapin](https://github.com/alesapin)).
#### New Feature
* Add feature for creating user-defined functions (UDF) as lambda expressions. Syntax `CREATE FUNCTION {function_name} as ({parameters}) -> {function core}`. Example `CREATE FUNCTION plus_one as (a) -> a + 1`. Authors @Realist007. [#27796](https://github.com/ClickHouse/ClickHouse/pull/27796) ([Maksim Kita](https://github.com/kitaisreal)) [#23978](https://github.com/ClickHouse/ClickHouse/pull/23978) ([Realist007](https://github.com/Realist007)).
* Added `Executable` storage engine and `executable` table function. It enables data processing with external scripts in streaming fashion. [#28102](https://github.com/ClickHouse/ClickHouse/pull/28102) ([Maksim Kita](https://github.com/kitaisreal)) ([ruct](https://github.com/ruct)).
* Added `ExecutablePool` storage engine. Similar to `Executable` but it's using a pool of long running processes. [#28518](https://github.com/ClickHouse/ClickHouse/pull/28518) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `ALTER TABLE ... MATERIALIZE COLUMN` query. [#27038](https://github.com/ClickHouse/ClickHouse/pull/27038) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Support for partitioned write into `s3` table function. [#23051](https://github.com/ClickHouse/ClickHouse/pull/23051) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Support `lz4` compression format (in addition to `gz`, `bz2`, `xz`, `zstd`) for data import / export. [#25310](https://github.com/ClickHouse/ClickHouse/pull/25310) ([Bharat Nallan](https://github.com/bharatnc)).
* Allow positional arguments under setting `enable_positional_arguments`. Closes [#2592](https://github.com/ClickHouse/ClickHouse/issues/2592). [#27530](https://github.com/ClickHouse/ClickHouse/pull/27530) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Accept user settings related to file formats in `SETTINGS` clause in `CREATE` query for s3 tables. This closes [#27580](https://github.com/ClickHouse/ClickHouse/issues/27580). [#28037](https://github.com/ClickHouse/ClickHouse/pull/28037) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow SSL connection for `RabbitMQ` engine. [#28365](https://github.com/ClickHouse/ClickHouse/pull/28365) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add `getServerPort` function to allow getting server port. When the port is not used by the server, throw an exception. [#27900](https://github.com/ClickHouse/ClickHouse/pull/27900) ([Amos Bird](https://github.com/amosbird)).
* Add conversion functions between "snowflake id" and `DateTime`, `DateTime64`. See [#27058](https://github.com/ClickHouse/ClickHouse/issues/27058). [#27704](https://github.com/ClickHouse/ClickHouse/pull/27704) ([jasine](https://github.com/jasine)).
* Add function `SHA512`. [#27830](https://github.com/ClickHouse/ClickHouse/pull/27830) ([zhanglistar](https://github.com/zhanglistar)).
* Add `log_queries_probability` setting that allows user to write to query_log only a sample of queries. Closes [#16609](https://github.com/ClickHouse/ClickHouse/issues/16609). [#27527](https://github.com/ClickHouse/ClickHouse/pull/27527) ([Nikolay Degterinsky](https://github.com/evillique)).
#### Experimental Feature
* `web` type of disks to store readonly tables on web server in form of static files. See [#23982](https://github.com/ClickHouse/ClickHouse/issues/23982). [#25251](https://github.com/ClickHouse/ClickHouse/pull/25251) ([Kseniia Sumarokova](https://github.com/kssenii)). This is mostly needed to faciliate testing of operation on shared storage and for easy importing of datasets. Not recommended to use before release 21.11.
* Added new commands `BACKUP` and `RESTORE`. [#21945](https://github.com/ClickHouse/ClickHouse/pull/21945) ([Vitaly Baranov](https://github.com/vitlibar)). This is under development and not intended to be used in current version.
#### Performance Improvement
* Speed up `sumIf` and `countIf` aggregation functions. [#28272](https://github.com/ClickHouse/ClickHouse/pull/28272) ([Raúl Marín](https://github.com/Algunenano)).
* Create virtual projection for `minmax` indices. Now, when `allow_experimental_projection_optimization` is enabled, queries will use minmax index instead of reading the data when possible. [#26286](https://github.com/ClickHouse/ClickHouse/pull/26286) ([Amos Bird](https://github.com/amosbird)).
* Introducing two checks in `sequenceMatch` and `sequenceCount` that allow for early exit when some deterministic part of the sequence pattern is missing from the events list. This change unlocks many queries that would previously fail due to reaching operations cap, and generally speeds up the pipeline. [#27729](https://github.com/ClickHouse/ClickHouse/pull/27729) ([Jakub Kuklis](https://github.com/jkuklis)).
* Enhance primary key analysis with always monotonic information of binary functions, notably non-zero constant division. [#28302](https://github.com/ClickHouse/ClickHouse/pull/28302) ([Amos Bird](https://github.com/amosbird)).
* Make `hasAll` filter condition leverage bloom filter data-skipping indexes. [#27984](https://github.com/ClickHouse/ClickHouse/pull/27984) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
* Speed up data parts loading by delaying table startup process. [#28313](https://github.com/ClickHouse/ClickHouse/pull/28313) ([Amos Bird](https://github.com/amosbird)).
* Fixed possible excessive number of conditions moved from `WHERE` to `PREWHERE` (optimization controlled by settings `optimize_move_to_prewhere`). [#28139](https://github.com/ClickHouse/ClickHouse/pull/28139) ([lthaooo](https://github.com/lthaooo)).
* Enable `optimize_distributed_group_by_sharding_key` by default. [#28105](https://github.com/ClickHouse/ClickHouse/pull/28105) ([Azat Khuzhin](https://github.com/azat)).
#### Improvement
* Check cluster name before creating `Distributed` table, do not allow to create a table with incorrect cluster name. Fixes [#27832](https://github.com/ClickHouse/ClickHouse/issues/27832). [#27927](https://github.com/ClickHouse/ClickHouse/pull/27927) ([tavplubix](https://github.com/tavplubix)).
* Add aggregate function `quantileBFloat16Weighted` similarly to other quantile...Weighted functions. This closes [#27745](https://github.com/ClickHouse/ClickHouse/issues/27745). [#27758](https://github.com/ClickHouse/ClickHouse/pull/27758) ([Ivan Novitskiy](https://github.com/RedClusive)).
* Allow to create dictionaries with empty attributes list. [#27905](https://github.com/ClickHouse/ClickHouse/pull/27905) ([Maksim Kita](https://github.com/kitaisreal)).
* Add interactive documentation in `clickhouse-client` about how to reset the password. This is useful in scenario when user has installed ClickHouse, set up the password and instantly forget it. See [#27750](https://github.com/ClickHouse/ClickHouse/issues/27750). [#27903](https://github.com/ClickHouse/ClickHouse/pull/27903) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support the case when the data is enclosed in array in `JSONAsString` input format. Closes [#25517](https://github.com/ClickHouse/ClickHouse/issues/25517). [#25633](https://github.com/ClickHouse/ClickHouse/pull/25633) ([Kruglov Pavel](https://github.com/Avogar)).
* Add new column `last_queue_update_exception` to `system.replicas` table. [#26843](https://github.com/ClickHouse/ClickHouse/pull/26843) ([nvartolomei](https://github.com/nvartolomei)).
* Support reconnections on failover for `MaterializedPostgreSQL` tables. Closes [#28529](https://github.com/ClickHouse/ClickHouse/issues/28529). [#28614](https://github.com/ClickHouse/ClickHouse/pull/28614) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Generate a unique server UUID on first server start. [#20089](https://github.com/ClickHouse/ClickHouse/pull/20089) ([Bharat Nallan](https://github.com/bharatnc)).
* Introduce `connection_wait_timeout` (default to 5 seconds, 0 - do not wait) setting for `MySQL` engine. [#28474](https://github.com/ClickHouse/ClickHouse/pull/28474) ([Azat Khuzhin](https://github.com/azat)).
* Do not allow creating `MaterializedPostgreSQL` with bad arguments. Closes [#28423](https://github.com/ClickHouse/ClickHouse/issues/28423). [#28430](https://github.com/ClickHouse/ClickHouse/pull/28430) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Use real tmp file instead of predefined "rows_sources" for vertical merges. This avoids generating garbage directories in tmp disks. [#28299](https://github.com/ClickHouse/ClickHouse/pull/28299) ([Amos Bird](https://github.com/amosbird)).
* Added `libhdfs3_conf` in server config instead of export env `LIBHDFS3_CONF` in clickhouse-server.service. This is for configuration of interaction with HDFS. [#28268](https://github.com/ClickHouse/ClickHouse/pull/28268) ([Zhichang Yu](https://github.com/yuzhichang)).
* Fix removing of parts in a Temporary state which can lead to an unexpected exception (`Part %name% doesn't exist`). Fixes [#23661](https://github.com/ClickHouse/ClickHouse/issues/23661). [#28221](https://github.com/ClickHouse/ClickHouse/pull/28221) [#28221](https://github.com/ClickHouse/ClickHouse/issues/28221)) ([Azat Khuzhin](https://github.com/azat)).
* Fix `zookeeper_log.address` (before the first patch in this PR the address was always `::`) and reduce number of calls `getpeername(2)` for this column (since each time entry for `zookeeper_log` is added `getpeername()` is called, cache this address in the zookeeper client to avoid this). [#28212](https://github.com/ClickHouse/ClickHouse/pull/28212) ([Azat Khuzhin](https://github.com/azat)).
* Support implicit conversions between index in operator `[]` and key of type `Map` (e.g. different `Int` types, `String` and `FixedString`). [#28096](https://github.com/ClickHouse/ClickHouse/pull/28096) ([Anton Popov](https://github.com/CurtizJ)).
* Support `ON CONFLICT` clause when inserting into PostgreSQL table engine or table function. Closes [#27727](https://github.com/ClickHouse/ClickHouse/issues/27727). [#28081](https://github.com/ClickHouse/ClickHouse/pull/28081) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Lower restrictions for `Enum` data type to allow attaching compatible data. Closes [#26672](https://github.com/ClickHouse/ClickHouse/issues/26672). [#28028](https://github.com/ClickHouse/ClickHouse/pull/28028) ([Dmitry Novik](https://github.com/novikd)).
* Add a setting `empty_result_for_aggregation_by_constant_keys_on_empty_set` to control the behavior of grouping by constant keys on empty set. This is to bring back the old baviour of [#6842](https://github.com/ClickHouse/ClickHouse/issues/6842). [#27932](https://github.com/ClickHouse/ClickHouse/pull/27932) ([Amos Bird](https://github.com/amosbird)).
* Added `replication_wait_for_inactive_replica_timeout` setting. It allows to specify how long to wait for inactive replicas to execute `ALTER`/`OPTIMZE`/`TRUNCATE` query (default is 120 seconds). If `replication_alter_partitions_sync` is 2 and some replicas are not active for more than `replication_wait_for_inactive_replica_timeout` seconds, then `UNFINISHED` will be thrown. [#27931](https://github.com/ClickHouse/ClickHouse/pull/27931) ([tavplubix](https://github.com/tavplubix)).
* Support lambda argument for `APPLY` column transformer which allows applying functions with more than one argument. This is for [#27877](https://github.com/ClickHouse/ClickHouse/issues/27877). [#27901](https://github.com/ClickHouse/ClickHouse/pull/27901) ([Amos Bird](https://github.com/amosbird)).
* Enable `tcp_keep_alive_timeout` by default. [#27882](https://github.com/ClickHouse/ClickHouse/pull/27882) ([Azat Khuzhin](https://github.com/azat)).
* Improve remote query cancelation (in case of remote server abnormaly terminated). [#27881](https://github.com/ClickHouse/ClickHouse/pull/27881) ([Azat Khuzhin](https://github.com/azat)).
* Use Multipart copy upload for large S3 objects. [#27858](https://github.com/ClickHouse/ClickHouse/pull/27858) ([ianton-ru](https://github.com/ianton-ru)).
* Allow symlink traversal for library dictionaty path. [#27815](https://github.com/ClickHouse/ClickHouse/pull/27815) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Now `ALTER MODIFY COLUM` `T` to `Nullable(T)` doesn't require mutation. [#27787](https://github.com/ClickHouse/ClickHouse/pull/27787) ([victorgao](https://github.com/kafka1991)).
* Don't silently ignore errors and don't count delays in `ReadBufferFromS3`. [#27484](https://github.com/ClickHouse/ClickHouse/pull/27484) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Improve `ALTER ... MATERIALIZE TTL` by recalculating metadata only without actual TTL action. [#27019](https://github.com/ClickHouse/ClickHouse/pull/27019) ([lthaooo](https://github.com/lthaooo)).
* Allow reading the list of custom top level domains without a new line at EOF. [#28213](https://github.com/ClickHouse/ClickHouse/pull/28213) ([Azat Khuzhin](https://github.com/azat)).
#### Bug Fix
* Fix cases, when reading compressed data from `carbon-clickhouse` fails with 'attempt to read after end of file'. Closes [#26149](https://github.com/ClickHouse/ClickHouse/issues/26149). [#28150](https://github.com/ClickHouse/ClickHouse/pull/28150) ([FArthur-cmd](https://github.com/FArthur-cmd)).
* Fix checking access grants when executing `GRANT WITH REPLACE` statement with `ON CLUSTER` clause. This PR improves fix [#27001](https://github.com/ClickHouse/ClickHouse/pull/27701). [#27983](https://github.com/ClickHouse/ClickHouse/pull/27983) ([Vitaly Baranov](https://github.com/vitlibar)).
* Allow selecting with `extremes = 1` from a column of the type `LowCardinality(UUID)`. [#27918](https://github.com/ClickHouse/ClickHouse/pull/27918) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix PostgreSQL-style cast (`::` operator) with negative numbers. [#27876](https://github.com/ClickHouse/ClickHouse/pull/27876) ([Anton Popov](https://github.com/CurtizJ)).
* After [#26864](https://github.com/ClickHouse/ClickHouse/pull/26864). Fix shutdown of `NamedSessionStorage`: session contexts stored in `NamedSessionStorage` are now destroyed before destroying the global context. [#27875](https://github.com/ClickHouse/ClickHouse/pull/27875) ([Vitaly Baranov](https://github.com/vitlibar)).
* Bugfix for `windowFunnel` "strict" mode. This fixes [#27469](https://github.com/ClickHouse/ClickHouse/issues/27469). [#27563](https://github.com/ClickHouse/ClickHouse/pull/27563) ([achimbab](https://github.com/achimbab)).
* Fix infinite loop while reading truncated `bzip2` archive. [#28543](https://github.com/ClickHouse/ClickHouse/pull/28543) ([Azat Khuzhin](https://github.com/azat)).
* Fix UUID overlap in `DROP TABLE` for internal DDL from `MaterializedMySQL`. MaterializedMySQL is an experimental feature. [#28533](https://github.com/ClickHouse/ClickHouse/pull/28533) ([Azat Khuzhin](https://github.com/azat)).
* Fix `There is no subcolumn` error, while select from tables, which have `Nested` columns and scalar columns with dot in name and the same prefix as `Nested` (e.g. `n.id UInt32, n.arr1 Array(UInt64), n.arr2 Array(UInt64)`). [#28531](https://github.com/ClickHouse/ClickHouse/pull/28531) ([Anton Popov](https://github.com/CurtizJ)).
* Fix bug which can lead to error `Existing table metadata in ZooKeeper differs in sorting key expression.` after ALTER of `ReplicatedVersionedCollapsingMergeTree`. Fixes [#28515](https://github.com/ClickHouse/ClickHouse/issues/28515). [#28528](https://github.com/ClickHouse/ClickHouse/pull/28528) ([alesapin](https://github.com/alesapin)).
* Fixed possible ZooKeeper watches leak (minor issue) on background processing of distributed DDL queue. Closes [#26036](https://github.com/ClickHouse/ClickHouse/issues/26036). [#28446](https://github.com/ClickHouse/ClickHouse/pull/28446) ([tavplubix](https://github.com/tavplubix)).
* Fix missing quoting of table names in `MaterializedPostgreSQL` engine. Closes [#28316](https://github.com/ClickHouse/ClickHouse/issues/28316). [#28433](https://github.com/ClickHouse/ClickHouse/pull/28433) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix the wrong behaviour of non joined rows from nullable column. Close [#27691](https://github.com/ClickHouse/ClickHouse/issues/27691). [#28349](https://github.com/ClickHouse/ClickHouse/pull/28349) ([vdimir](https://github.com/vdimir)).
* Fix NOT-IN index optimization when not all key columns are used. This fixes [#28120](https://github.com/ClickHouse/ClickHouse/issues/28120). [#28315](https://github.com/ClickHouse/ClickHouse/pull/28315) ([Amos Bird](https://github.com/amosbird)).
* Fix intersecting parts due to new part had been replaced with an empty part. [#28310](https://github.com/ClickHouse/ClickHouse/pull/28310) ([Azat Khuzhin](https://github.com/azat)).
* Fix inconsistent result in queries with `ORDER BY` and `Merge` tables with enabled setting `optimize_read_in_order`. [#28266](https://github.com/ClickHouse/ClickHouse/pull/28266) ([Anton Popov](https://github.com/CurtizJ)).
* Fix possible read of uninitialized memory for queries with `Nullable(LowCardinality)` type and the setting `extremes` set to 1. Fixes [#28165](https://github.com/ClickHouse/ClickHouse/issues/28165). [#28205](https://github.com/ClickHouse/ClickHouse/pull/28205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Multiple small fixes for projections. See detailed description in the PR. [#28178](https://github.com/ClickHouse/ClickHouse/pull/28178) ([Amos Bird](https://github.com/amosbird)).
* Fix extremely rare segfaults on shutdown due to incorrect order of context/config reloader shutdown. [#28088](https://github.com/ClickHouse/ClickHouse/pull/28088) ([nvartolomei](https://github.com/nvartolomei)).
* Fix handling null value with type of `Nullable(String)` in function `JSONExtract`. This fixes [#27929](https://github.com/ClickHouse/ClickHouse/issues/27929) and [#27930](https://github.com/ClickHouse/ClickHouse/issues/27930). This was introduced in https://github.com/ClickHouse/ClickHouse/pull/25452 . [#27939](https://github.com/ClickHouse/ClickHouse/pull/27939) ([Amos Bird](https://github.com/amosbird)).
* Multiple fixes for the new `clickhouse-keeper` tool. Fix a rare bug in `clickhouse-keeper` when the client can receive a watch response before request-response. [#28197](https://github.com/ClickHouse/ClickHouse/pull/28197) ([alesapin](https://github.com/alesapin)). Fix incorrect behavior in `clickhouse-keeper` when list watches (`getChildren`) triggered with `set` requests for children. [#28190](https://github.com/ClickHouse/ClickHouse/pull/28190) ([alesapin](https://github.com/alesapin)). Fix rare case when changes of `clickhouse-keeper` settings may lead to lost logs and server hung. [#28360](https://github.com/ClickHouse/ClickHouse/pull/28360) ([alesapin](https://github.com/alesapin)). Fix bug in `clickhouse-keeper` which can lead to endless logs when `rotate_logs_interval` decreased. [#28152](https://github.com/ClickHouse/ClickHouse/pull/28152) ([alesapin](https://github.com/alesapin)).
#### Build/Testing/Packaging Improvement
* Enable Thread Fuzzer in Stress Test. Thread Fuzzer is ClickHouse feature that allows to test more permutations of thread scheduling and discover more potential issues. This closes [#9813](https://github.com/ClickHouse/ClickHouse/issues/9813). This closes [#9814](https://github.com/ClickHouse/ClickHouse/issues/9814). This closes [#9515](https://github.com/ClickHouse/ClickHouse/issues/9515). This closes [#9516](https://github.com/ClickHouse/ClickHouse/issues/9516). [#27538](https://github.com/ClickHouse/ClickHouse/pull/27538) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add new log level `test` for testing environments. It is even more verbose than the default `trace`. [#28559](https://github.com/ClickHouse/ClickHouse/pull/28559) ([alesapin](https://github.com/alesapin)).
* Print out git status information at CMake configure stage. [#28047](https://github.com/ClickHouse/ClickHouse/pull/28047) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
* Temporarily switched ubuntu apt repository to mirror ru.archive.ubuntu.com as the default one (archive.ubuntu.com) is not responding from our CI. [#28016](https://github.com/ClickHouse/ClickHouse/pull/28016) ([Ilya Yatsishin](https://github.com/qoega)).
### ClickHouse release v21.9, 2021-09-09
#### Backward Incompatible Change
* Do not output trailing zeros in text representation of `Decimal` types. Example: `1.23` will be printed instead of `1.230000` for decimal with scale 6. This closes [#15794](https://github.com/ClickHouse/ClickHouse/issues/15794). It may introduce slight incompatibility if your applications somehow relied on the trailing zeros. Serialization in output formats can be controlled with the setting `output_format_decimal_trailing_zeros`. Implementation of `toString` and casting to String is changed unconditionally. [#27680](https://github.com/ClickHouse/ClickHouse/pull/27680) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Do not allow to apply parametric aggregate function with `-Merge` combinator to aggregate function state if state was produced by aggregate function with different parameters. For example, state of `fooState(42)(x)` cannot be finalized with `fooMerge(s)` or `fooMerge(123)(s)`, parameters must be specified explicitly like `fooMerge(42)(s)` and must be equal. It does not affect some special aggregate functions like `quantile` and `sequence*` that use parameters for finalization only. [#26847](https://github.com/ClickHouse/ClickHouse/pull/26847) ([tavplubix](https://github.com/tavplubix)).
* Under clickhouse-local, always treat local addresses with a port as remote. [#26736](https://github.com/ClickHouse/ClickHouse/pull/26736) ([Raúl Marín](https://github.com/Algunenano)).
* Fix the issue that in case of some sophisticated query with column aliases identical to the names of expressions, bad cast may happen. This fixes [#25447](https://github.com/ClickHouse/ClickHouse/issues/25447). This fixes [#26914](https://github.com/ClickHouse/ClickHouse/issues/26914). This fix may introduce backward incompatibility: if there are different expressions with identical names, exception will be thrown. It may break some rare cases when `enable_optimize_predicate_expression` is set. [#26639](https://github.com/ClickHouse/ClickHouse/pull/26639) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now, scalar subquery always returns `Nullable` result if it's type can be `Nullable`. It is needed because in case of empty subquery it's result should be `Null`. Previously, it was possible to get error about incompatible types (type deduction does not execute scalar subquery, and it could use not-nullable type). Scalar subquery with empty result which can't be converted to `Nullable` (like `Array` or `Tuple`) now throws error. Fixes [#25411](https://github.com/ClickHouse/ClickHouse/issues/25411). [#26423](https://github.com/ClickHouse/ClickHouse/pull/26423) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Introduce syntax for here documents. Example `SELECT $doc$ VALUE $doc$`. [#26671](https://github.com/ClickHouse/ClickHouse/pull/26671) ([Maksim Kita](https://github.com/kitaisreal)). This change is backward incompatible if in query there are identifiers that contain `$` [#28768](https://github.com/ClickHouse/ClickHouse/issues/28768).
* Now indices can handle Nullable types, including `isNull` and `isNotNull`. [#12433](https://github.com/ClickHouse/ClickHouse/pull/12433) and [#12455](https://github.com/ClickHouse/ClickHouse/pull/12455) ([Amos Bird](https://github.com/amosbird)) and [#27250](https://github.com/ClickHouse/ClickHouse/pull/27250) ([Azat Khuzhin](https://github.com/azat)). But this was done with on-disk format changes, and even though new server can read old data, old server cannot. Also, in case you have `MINMAX` data skipping indices, you may get `Data after mutation/merge is not byte-identical` error, since new index will have `.idx2` extension while before it was `.idx`. That said, that you should not delay updating all existing replicas, in this case, otherwise, if old replica (<21.9) will download data from new replica with 21.9+ it will not be able to apply index for downloaded part.
#### New Feature
* Implementation of short circuit function evaluation, closes [#12587](https://github.com/ClickHouse/ClickHouse/issues/12587). Add settings `short_circuit_function_evaluation` to configure short circuit function evaluation. [#23367](https://github.com/ClickHouse/ClickHouse/pull/23367) ([Kruglov Pavel](https://github.com/Avogar)).
* Add support for INTERSECT, EXCEPT, ANY, ALL operators. [#24757](https://github.com/ClickHouse/ClickHouse/pull/24757) ([Kirill Ershov](https://github.com/zdikov)). ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add support for encryption at the virtual file system level (data encryption at rest) using AES-CTR algorithm. [#24206](https://github.com/ClickHouse/ClickHouse/pull/24206) ([Latysheva Alexandra](https://github.com/alexelex)). ([Vitaly Baranov](https://github.com/vitlibar)) [#26733](https://github.com/ClickHouse/ClickHouse/pull/26733) [#26377](https://github.com/ClickHouse/ClickHouse/pull/26377) [#26465](https://github.com/ClickHouse/ClickHouse/pull/26465).
* Added natural language processing (NLP) functions for tokenization, stemming, lemmatizing and search in synonyms extensions. [#24997](https://github.com/ClickHouse/ClickHouse/pull/24997) ([Nikolay Degterinsky](https://github.com/evillique)).
* Added integration with S2 geometry library. [#24980](https://github.com/ClickHouse/ClickHouse/pull/24980) ([Andr0901](https://github.com/Andr0901)). ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Add SQLite table engine, table function, database engine. [#24194](https://github.com/ClickHouse/ClickHouse/pull/24194) ([Arslan Gumerov](https://github.com/g-arslan)). ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added support for custom query for `MySQL`, `PostgreSQL`, `ClickHouse`, `JDBC`, `Cassandra` dictionary source. Closes [#1270](https://github.com/ClickHouse/ClickHouse/issues/1270). [#26995](https://github.com/ClickHouse/ClickHouse/pull/26995) ([Maksim Kita](https://github.com/kitaisreal)).
* Add shared (replicated) storage of user, roles, row policies, quotas and settings profiles through ZooKeeper. [#27426](https://github.com/ClickHouse/ClickHouse/pull/27426) ([Kevin Michel](https://github.com/kmichel-aiven)).
* Add compression for `INTO OUTFILE` that automatically choose compression algorithm. Closes [#3473](https://github.com/ClickHouse/ClickHouse/issues/3473). [#27134](https://github.com/ClickHouse/ClickHouse/pull/27134) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Add `INSERT ... FROM INFILE` similarly to `SELECT ... INTO OUTFILE`. [#27655](https://github.com/ClickHouse/ClickHouse/pull/27655) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Added `complex_key_range_hashed` dictionary. Closes [#22029](https://github.com/ClickHouse/ClickHouse/issues/22029). [#27629](https://github.com/ClickHouse/ClickHouse/pull/27629) ([Maksim Kita](https://github.com/kitaisreal)).
* Support expressions in JOIN ON section. Close [#21868](https://github.com/ClickHouse/ClickHouse/issues/21868). [#24420](https://github.com/ClickHouse/ClickHouse/pull/24420) ([Vladimir C](https://github.com/vdimir)).
* When client connects to server, it receives information about all warnings that are already were collected by server. (It can be disabled by using option `--no-warnings`). Add `system.warnings` table to collect warnings about server configuration. [#26246](https://github.com/ClickHouse/ClickHouse/pull/26246) ([Filatenkov Artur](https://github.com/FArthur-cmd)). [#26282](https://github.com/ClickHouse/ClickHouse/pull/26282) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Allow using constant expressions from with and select in aggregate function parameters. Close [#10945](https://github.com/ClickHouse/ClickHouse/issues/10945). [#27531](https://github.com/ClickHouse/ClickHouse/pull/27531) ([abel-cheng](https://github.com/abel-cheng)).
* Add `tupleToNameValuePairs`, a function that turns a named tuple into an array of pairs. [#27505](https://github.com/ClickHouse/ClickHouse/pull/27505) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
* Add support for `bzip2` compression method for import/export. Closes [#22428](https://github.com/ClickHouse/ClickHouse/issues/22428). [#27377](https://github.com/ClickHouse/ClickHouse/pull/27377) ([Nikolay Degterinsky](https://github.com/evillique)).
* Added `bitmapSubsetOffsetLimit(bitmap, offset, cardinality_limit)` function. It creates a subset of bitmap limit the results to `cardinality_limit` with offset of `offset`. [#27234](https://github.com/ClickHouse/ClickHouse/pull/27234) ([DHBin](https://github.com/DHBin)).
* Add column `default_database` to `system.users`. [#27054](https://github.com/ClickHouse/ClickHouse/pull/27054) ([kevin wan](https://github.com/MaxWk)).
* Supported `cluster` macros inside table functions 'cluster' and 'clusterAllReplicas'. [#26913](https://github.com/ClickHouse/ClickHouse/pull/26913) ([polyprogrammist](https://github.com/PolyProgrammist)).
* Add new functions `currentRoles()`, `enabledRoles()`, `defaultRoles()`. [#26780](https://github.com/ClickHouse/ClickHouse/pull/26780) ([Vitaly Baranov](https://github.com/vitlibar)).
* New functions `currentProfiles()`, `enabledProfiles()`, `defaultProfiles()`. [#26714](https://github.com/ClickHouse/ClickHouse/pull/26714) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add functions that return (initial_)query_id of the current query. This closes [#23682](https://github.com/ClickHouse/ClickHouse/issues/23682). [#26410](https://github.com/ClickHouse/ClickHouse/pull/26410) ([Alexey Boykov](https://github.com/mathalex)).
* Add `REPLACE GRANT` feature. [#26384](https://github.com/ClickHouse/ClickHouse/pull/26384) ([Caspian](https://github.com/Cas-pian)).
* `EXPLAIN` query now has `EXPLAIN ESTIMATE ...` mode that will show information about read rows, marks and parts from MergeTree tables. Closes [#23941](https://github.com/ClickHouse/ClickHouse/issues/23941). [#26131](https://github.com/ClickHouse/ClickHouse/pull/26131) ([fastio](https://github.com/fastio)).
* Added `system.zookeeper_log` table. All actions of ZooKeeper client are logged into this table. Implements [#25449](https://github.com/ClickHouse/ClickHouse/issues/25449). [#26129](https://github.com/ClickHouse/ClickHouse/pull/26129) ([tavplubix](https://github.com/tavplubix)).
* Zero-copy replication for `ReplicatedMergeTree` over `HDFS` storage. [#25918](https://github.com/ClickHouse/ClickHouse/pull/25918) ([Zhichang Yu](https://github.com/yuzhichang)).
* Allow to insert Nested type as array of structs in `Arrow`, `ORC` and `Parquet` input format. [#25902](https://github.com/ClickHouse/ClickHouse/pull/25902) ([Kruglov Pavel](https://github.com/Avogar)).
* Add a new datatype `Date32` (store data as Int32), support date range same with `DateTime64` support load parquet date32 to ClickHouse `Date32` Add new function `toDate32` like `toDate`. [#25774](https://github.com/ClickHouse/ClickHouse/pull/25774) ([LiuNeng](https://github.com/liuneng1994)).
* Allow setting default database for users. [#25268](https://github.com/ClickHouse/ClickHouse/issues/25268). [#25687](https://github.com/ClickHouse/ClickHouse/pull/25687) ([kevin wan](https://github.com/MaxWk)).
* Add an optional parameter to `MongoDB` engine to accept connection string options and support SSL connection. Closes [#21189](https://github.com/ClickHouse/ClickHouse/issues/21189). Closes [#21041](https://github.com/ClickHouse/ClickHouse/issues/21041). [#22045](https://github.com/ClickHouse/ClickHouse/pull/22045) ([Omar Bazaraa](https://github.com/OmarBazaraa)).
#### Experimental Feature
* Added a compression codec `AES_128_GCM_SIV` which encrypts columns instead of compressing them. [#19896](https://github.com/ClickHouse/ClickHouse/pull/19896) ([PHO](https://github.com/depressed-pho)). Will be rewritten, do not use.
* Rename `MaterializeMySQL` to `MaterializedMySQL`. [#26822](https://github.com/ClickHouse/ClickHouse/pull/26822) ([tavplubix](https://github.com/tavplubix)).
#### Performance Improvement
* Improve the performance of fast queries when `max_execution_time = 0` by reducing the number of `clock_gettime` system calls. [#27325](https://github.com/ClickHouse/ClickHouse/pull/27325) ([filimonov](https://github.com/filimonov)).
* Specialize date time related comparison to achieve better performance. This fixes [#27083](https://github.com/ClickHouse/ClickHouse/issues/27083) . [#27122](https://github.com/ClickHouse/ClickHouse/pull/27122) ([Amos Bird](https://github.com/amosbird)).
* Share file descriptors in concurrent reads of the same files. There is no noticeable performance difference on Linux. But the number of opened files will be significantly (10..100 times) lower on typical servers and it makes operations easier. See [#26214](https://github.com/ClickHouse/ClickHouse/issues/26214). [#26768](https://github.com/ClickHouse/ClickHouse/pull/26768) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve latency of short queries, that require reading from tables with large number of columns. [#26371](https://github.com/ClickHouse/ClickHouse/pull/26371) ([Anton Popov](https://github.com/CurtizJ)).
* Don't build sets for indices when analyzing a query. [#26365](https://github.com/ClickHouse/ClickHouse/pull/26365) ([Raúl Marín](https://github.com/Algunenano)).
* Vectorize the SUM of Nullable integer types with native representation ([David Manzanares](https://github.com/davidmanzanares), [Raúl Marín](https://github.com/Algunenano)). [#26248](https://github.com/ClickHouse/ClickHouse/pull/26248) ([Raúl Marín](https://github.com/Algunenano)).
* Compile expressions involving columns with `Enum` types. [#26237](https://github.com/ClickHouse/ClickHouse/pull/26237) ([Maksim Kita](https://github.com/kitaisreal)).
* Compile aggregate functions `groupBitOr`, `groupBitAnd`, `groupBitXor`. [#26161](https://github.com/ClickHouse/ClickHouse/pull/26161) ([Maksim Kita](https://github.com/kitaisreal)).
* Improved memory usage with better block size prediction when reading empty DEFAULT columns. Closes [#17317](https://github.com/ClickHouse/ClickHouse/issues/17317). [#25917](https://github.com/ClickHouse/ClickHouse/pull/25917) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Reduce memory usage and number of read rows in queries with `ORDER BY primary_key`. [#25721](https://github.com/ClickHouse/ClickHouse/pull/25721) ([Anton Popov](https://github.com/CurtizJ)).
* Enable `distributed_push_down_limit` by default. [#27104](https://github.com/ClickHouse/ClickHouse/pull/27104) ([Azat Khuzhin](https://github.com/azat)).
* Make `toTimeZone` monotonicity when timeZone is a constant value to support partition puring when use sql like:. [#26261](https://github.com/ClickHouse/ClickHouse/pull/26261) ([huangzhaowei](https://github.com/SaintBacchus)).
#### Improvement
* Mark window functions as ready for general use. Remove the `allow_experimental_window_functions` setting. [#27184](https://github.com/ClickHouse/ClickHouse/pull/27184) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Improve compatibility with non-whole-minute timezone offsets. [#27080](https://github.com/ClickHouse/ClickHouse/pull/27080) ([Raúl Marín](https://github.com/Algunenano)).
* If file descriptor in `File` table is regular file - allow to read multiple times from it. It allows `clickhouse-local` to read multiple times from stdin (with multiple SELECT queries or subqueries) if stdin is a regular file like `clickhouse-local --query "SELECT * FROM table UNION ALL SELECT * FROM table" ... < file`. This closes [#11124](https://github.com/ClickHouse/ClickHouse/issues/11124). Co-authored with ([alexey-milovidov](https://github.com/alexey-milovidov)). [#25960](https://github.com/ClickHouse/ClickHouse/pull/25960) ([BoloniniD](https://github.com/BoloniniD)).
* Remove duplicate index analysis and avoid possible invalid limit checks during projection analysis. [#27742](https://github.com/ClickHouse/ClickHouse/pull/27742) ([Amos Bird](https://github.com/amosbird)).
* Enable query parameters to be passed in the body of HTTP requests. [#27706](https://github.com/ClickHouse/ClickHouse/pull/27706) ([Hermano Lustosa](https://github.com/hllustosa)).
* Disallow `arrayJoin` on partition expressions. [#27648](https://github.com/ClickHouse/ClickHouse/pull/27648) ([Raúl Marín](https://github.com/Algunenano)).
* Log client IP address if authentication fails. [#27514](https://github.com/ClickHouse/ClickHouse/pull/27514) ([Misko Lee](https://github.com/imiskolee)).
* Use bytes instead of strings for binary data in the GRPC protocol. [#27431](https://github.com/ClickHouse/ClickHouse/pull/27431) ([Vitaly Baranov](https://github.com/vitlibar)).
* Send response with error message if HTTP port is not set and user tries to send HTTP request to TCP port. [#27385](https://github.com/ClickHouse/ClickHouse/pull/27385) ([Braulio Valdivielso Martínez](https://github.com/BraulioVM)).
* Add `_CAST` function for internal usage, which will not preserve type nullability, but non-internal cast will preserve according to setting `cast_keep_nullable`. Closes [#12636](https://github.com/ClickHouse/ClickHouse/issues/12636). [#27382](https://github.com/ClickHouse/ClickHouse/pull/27382) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add setting `log_formatted_queries` to log additional formatted query into `system.query_log`. It's useful for normalized query analysis because functions like `normalizeQuery` and `normalizeQueryKeepNames` don't parse/format queries in order to achieve better performance. [#27380](https://github.com/ClickHouse/ClickHouse/pull/27380) ([Amos Bird](https://github.com/amosbird)).
* Add two settings `max_hyperscan_regexp_length` and `max_hyperscan_regexp_total_length` to prevent huge regexp being used in hyperscan related functions, such as `multiMatchAny`. [#27378](https://github.com/ClickHouse/ClickHouse/pull/27378) ([Amos Bird](https://github.com/amosbird)).
* Memory consumed by bitmap aggregate functions now is taken into account for memory limits. This closes [#26555](https://github.com/ClickHouse/ClickHouse/issues/26555). [#27252](https://github.com/ClickHouse/ClickHouse/pull/27252) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add 10 seconds cache for S3 proxy resolver. [#27216](https://github.com/ClickHouse/ClickHouse/pull/27216) ([ianton-ru](https://github.com/ianton-ru)).
* Split global mutex into individual regexp construction. This helps avoid huge regexp construction blocking other related threads. [#27211](https://github.com/ClickHouse/ClickHouse/pull/27211) ([Amos Bird](https://github.com/amosbird)).
* Support schema for PostgreSQL database engine. Closes [#27166](https://github.com/ClickHouse/ClickHouse/issues/27166). [#27198](https://github.com/ClickHouse/ClickHouse/pull/27198) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Track memory usage in clickhouse-client. [#27191](https://github.com/ClickHouse/ClickHouse/pull/27191) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Try recording `query_kind` in `system.query_log` even when query fails to start. [#27182](https://github.com/ClickHouse/ClickHouse/pull/27182) ([Amos Bird](https://github.com/amosbird)).
* Added columns `replica_is_active` that maps replica name to is replica active status to table `system.replicas`. Closes [#27138](https://github.com/ClickHouse/ClickHouse/issues/27138). [#27180](https://github.com/ClickHouse/ClickHouse/pull/27180) ([Maksim Kita](https://github.com/kitaisreal)).
* Allow to pass query settings via server URI in Web UI. [#27177](https://github.com/ClickHouse/ClickHouse/pull/27177) ([kolsys](https://github.com/kolsys)).
* Add a new metric called `MaxPushedDDLEntryID` which is the maximum ddl entry id that current node push to zookeeper. [#27174](https://github.com/ClickHouse/ClickHouse/pull/27174) ([Fuwang Hu](https://github.com/fuwhu)).
* Improved the existence condition judgment and empty string node judgment when `clickhouse-keeper` creates znode. [#27125](https://github.com/ClickHouse/ClickHouse/pull/27125) ([小路](https://github.com/nicelulu)).
* Merge JOIN correctly handles empty set in the right. [#27078](https://github.com/ClickHouse/ClickHouse/pull/27078) ([Vladimir C](https://github.com/vdimir)).
* Now functions can be shard-level constants, which means if it's executed in the context of some distributed table, it generates a normal column, otherwise it produces a constant value. Notable functions are: `hostName()`, `tcpPort()`, `version()`, `buildId()`, `uptime()`, etc. [#27020](https://github.com/ClickHouse/ClickHouse/pull/27020) ([Amos Bird](https://github.com/amosbird)).
* Updated `extractAllGroupsHorizontal` - upper limit on the number of matches per row can be set via optional third argument. [#26961](https://github.com/ClickHouse/ClickHouse/pull/26961) ([Vasily Nemkov](https://github.com/Enmk)).
* Expose `RocksDB` statistics via system.rocksdb table. Read rocksdb options from ClickHouse config (`rocksdb...` keys). NOTE: ClickHouse does not rely on RocksDB, it is just one of the additional integration storage engines. [#26821](https://github.com/ClickHouse/ClickHouse/pull/26821) ([Azat Khuzhin](https://github.com/azat)).
* Less verbose internal RocksDB logs. NOTE: ClickHouse does not rely on RocksDB, it is just one of the additional integration storage engines. This closes [#26252](https://github.com/ClickHouse/ClickHouse/issues/26252). [#26789](https://github.com/ClickHouse/ClickHouse/pull/26789) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Changing default roles affects new sessions only. [#26759](https://github.com/ClickHouse/ClickHouse/pull/26759) ([Vitaly Baranov](https://github.com/vitlibar)).
* Watchdog is disabled in docker by default. Fix for not handling ctrl+c. [#26757](https://github.com/ClickHouse/ClickHouse/pull/26757) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* `SET PROFILE` now applies constraints too if they're set for a passed profile. [#26730](https://github.com/ClickHouse/ClickHouse/pull/26730) ([Vitaly Baranov](https://github.com/vitlibar)).
* Improve handling of `KILL QUERY` requests. [#26675](https://github.com/ClickHouse/ClickHouse/pull/26675) ([Raúl Marín](https://github.com/Algunenano)).
* `mapPopulatesSeries` function supports `Map` type. [#26663](https://github.com/ClickHouse/ClickHouse/pull/26663) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Fix excessive (x2) connect attempts with `skip_unavailable_shards`. [#26658](https://github.com/ClickHouse/ClickHouse/pull/26658) ([Azat Khuzhin](https://github.com/azat)).
* Avoid hanging `clickhouse-benchmark` if connection fails (i.e. on EMFILE). [#26656](https://github.com/ClickHouse/ClickHouse/pull/26656) ([Azat Khuzhin](https://github.com/azat)).
* Allow more threads to be used by the Kafka engine. [#26642](https://github.com/ClickHouse/ClickHouse/pull/26642) ([feihengye](https://github.com/feihengye)).
* Add round-robin support for `clickhouse-benchmark` (it does not differ from the regular multi host/port run except for statistics report). [#26607](https://github.com/ClickHouse/ClickHouse/pull/26607) ([Azat Khuzhin](https://github.com/azat)).
* Executable dictionaries (`executable`, `executable_pool`) enable creation with DDL query using `clickhouse-local`. Closes [#22355](https://github.com/ClickHouse/ClickHouse/issues/22355). [#26510](https://github.com/ClickHouse/ClickHouse/pull/26510) ([Maksim Kita](https://github.com/kitaisreal)).
* Set client query kind for `mysql` and `postgresql` compatibility protocol handlers. [#26498](https://github.com/ClickHouse/ClickHouse/pull/26498) ([anneji-dev](https://github.com/anneji-dev)).
* Apply `LIMIT` on the shards for queries like `SELECT * FROM dist ORDER BY key LIMIT 10` w/ `distributed_push_down_limit=1`. Avoid running `Distinct`/`LIMIT BY` steps for queries like `SELECT DISTINCT shading_key FROM dist ORDER BY key`. Now `distributed_push_down_limit` is respected by `optimize_distributed_group_by_sharding_key` optimization. [#26466](https://github.com/ClickHouse/ClickHouse/pull/26466) ([Azat Khuzhin](https://github.com/azat)).
* Updated protobuf to 3.17.3. Changelogs are available on https://github.com/protocolbuffers/protobuf/releases. [#26424](https://github.com/ClickHouse/ClickHouse/pull/26424) ([Ilya Yatsishin](https://github.com/qoega)).
* Enable `use_hedged_requests` setting that allows to mitigate tail latencies on large clusters. [#26380](https://github.com/ClickHouse/ClickHouse/pull/26380) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve behaviour with non-existing host in user allowed host list. [#26368](https://github.com/ClickHouse/ClickHouse/pull/26368) ([ianton-ru](https://github.com/ianton-ru)).
* Add ability to set `Distributed` directory monitor settings via CREATE TABLE (i.e. `CREATE TABLE dist (key Int) Engine=Distributed(cluster, db, table) SETTINGS monitor_batch_inserts=1` and similar). [#26336](https://github.com/ClickHouse/ClickHouse/pull/26336) ([Azat Khuzhin](https://github.com/azat)).
* Save server address in history URLs in web UI if it differs from the origin of web UI. This closes [#26044](https://github.com/ClickHouse/ClickHouse/issues/26044). [#26322](https://github.com/ClickHouse/ClickHouse/pull/26322) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add events to profile calls to `sleep` / `sleepEachRow`. [#26320](https://github.com/ClickHouse/ClickHouse/pull/26320) ([Raúl Marín](https://github.com/Algunenano)).
* Allow to reuse connections of shards among different clusters. It also avoids creating new connections when using `cluster` table function. [#26318](https://github.com/ClickHouse/ClickHouse/pull/26318) ([Amos Bird](https://github.com/amosbird)).
* Control the execution period of clear old temporary directories by parameter with default value. [#26212](https://github.com/ClickHouse/ClickHouse/issues/26212). [#26313](https://github.com/ClickHouse/ClickHouse/pull/26313) ([fastio](https://github.com/fastio)).
* Add a setting `function_range_max_elements_in_block` to tune the safety threshold for data volume generated by function `range`. This closes [#26303](https://github.com/ClickHouse/ClickHouse/issues/26303). [#26305](https://github.com/ClickHouse/ClickHouse/pull/26305) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Check hash function at table creation, not at sampling. Add settings for MergeTree, if someone create a table with incorrect sampling column but sampling never be used, disable this settings for starting the server without exception. [#26256](https://github.com/ClickHouse/ClickHouse/pull/26256) ([zhaoyu](https://github.com/zxc111)).
* Added `output_format_avro_string_column_pattern` setting to put specified String columns to Avro as string instead of default bytes. Implements [#22414](https://github.com/ClickHouse/ClickHouse/issues/22414). [#26245](https://github.com/ClickHouse/ClickHouse/pull/26245) ([Ilya Golshtein](https://github.com/ilejn)).
* Add information about column sizes in `system.columns` table for `Log` and `TinyLog` tables. This closes [#9001](https://github.com/ClickHouse/ClickHouse/issues/9001). [#26241](https://github.com/ClickHouse/ClickHouse/pull/26241) ([Nikolay Degterinsky](https://github.com/evillique)).
* Don't throw exception when querying `system.detached_parts` table if there is custom disk configuration and `detached` directory does not exist on some disks. This closes [#26078](https://github.com/ClickHouse/ClickHouse/issues/26078). [#26236](https://github.com/ClickHouse/ClickHouse/pull/26236) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Check for non-deterministic functions in keys, including constant expressions like `now()`, `today()`. This closes [#25875](https://github.com/ClickHouse/ClickHouse/issues/25875). This closes [#11333](https://github.com/ClickHouse/ClickHouse/issues/11333). [#26235](https://github.com/ClickHouse/ClickHouse/pull/26235) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* convert timestamp and timestamptz data types to `DateTime64` in PostgreSQL table engine. [#26234](https://github.com/ClickHouse/ClickHouse/pull/26234) ([jasine](https://github.com/jasine)).
* Apply aggressive IN index analysis for projections so that better projection candidate can be selected. [#26218](https://github.com/ClickHouse/ClickHouse/pull/26218) ([Amos Bird](https://github.com/amosbird)).
* Remove GLOBAL keyword for IN when scalar function is passed. In previous versions, if user specified `GLOBAL IN f(x)` exception was thrown. [#26217](https://github.com/ClickHouse/ClickHouse/pull/26217) ([Amos Bird](https://github.com/amosbird)).
* Add error id (like `BAD_ARGUMENTS`) to exception messages. This closes [#25862](https://github.com/ClickHouse/ClickHouse/issues/25862). [#26172](https://github.com/ClickHouse/ClickHouse/pull/26172) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix incorrect output with --progress option for clickhouse-local. Progress bar will be cleared once it gets to 100% - same as it is done for clickhouse-client. Closes [#17484](https://github.com/ClickHouse/ClickHouse/issues/17484). [#26128](https://github.com/ClickHouse/ClickHouse/pull/26128) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add `merge_selecting_sleep_ms` setting. [#26120](https://github.com/ClickHouse/ClickHouse/pull/26120) ([lthaooo](https://github.com/lthaooo)).
* Remove complicated usage of Linux AIO with one block readahead and replace it with plain simple synchronous IO with O_DIRECT. In previous versions, the setting `min_bytes_to_use_direct_io` may not work correctly if `max_threads` is greater than one. Reading with direct IO (that is disabled by default for queries and enabled by default for large merges) will work in less efficient way. This closes [#25997](https://github.com/ClickHouse/ClickHouse/issues/25997). [#26003](https://github.com/ClickHouse/ClickHouse/pull/26003) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Flush `Distributed` table on `REPLACE TABLE` query. Resolves [#24566](https://github.com/ClickHouse/ClickHouse/issues/24566) - Do not replace (or create) table on `[CREATE OR] REPLACE TABLE ... AS SELECT` query if insertion into new table fails. Resolves [#23175](https://github.com/ClickHouse/ClickHouse/issues/23175). [#25895](https://github.com/ClickHouse/ClickHouse/pull/25895) ([tavplubix](https://github.com/tavplubix)).
* Add `views` column to system.query_log containing the names of the (materialized or live) views executed by the query. Adds a new log table (`system.query_views_log`) that contains information about each view executed during a query. Modifies view execution: When an exception is thrown while executing a view, any view that has already startedwill continue running until it finishes. This used to be the behaviour under parallel_view_processing=true and now it's always the same behaviour. - Dependent views now report reading progress to the context. [#25714](https://github.com/ClickHouse/ClickHouse/pull/25714) ([Raúl Marín](https://github.com/Algunenano)).
* Do connection draining asynchonously upon finishing executing distributed queries. A new server setting is added `max_threads_for_connection_collector` which specifies the number of workers to recycle connections in background. If the pool is full, connection will be drained synchronously but a bit different than before: It's drained after we send EOS to client, query will succeed immediately after receiving enough data, and any exception will be logged instead of throwing to the client. Added setting `drain_timeout` (3 seconds by default). Connection draining will disconnect upon timeout. [#25674](https://github.com/ClickHouse/ClickHouse/pull/25674) ([Amos Bird](https://github.com/amosbird)).
* Support for multiple includes in configuration. It is possible to include users configuration, remote servers configuration from multiple sources. Simply place `<include />` element with `from_zk`, `from_env` or `incl` attribute and it will be replaced with the substitution. [#24404](https://github.com/ClickHouse/ClickHouse/pull/24404) ([nvartolomei](https://github.com/nvartolomei)).
* Fix multiple block insertion into distributed table with `insert_distributed_one_random_shard = 1`. This is a marginal feature. Mark as improvement. [#23140](https://github.com/ClickHouse/ClickHouse/pull/23140) ([Amos Bird](https://github.com/amosbird)).
* Support `LowCardinality` and `FixedString` keys/values for `Map` type. [#21543](https://github.com/ClickHouse/ClickHouse/pull/21543) ([hexiaoting](https://github.com/hexiaoting)).
* Enable reloading of local disk config. [#19526](https://github.com/ClickHouse/ClickHouse/pull/19526) ([taiyang-li](https://github.com/taiyang-li)).
#### Bug Fix
* Fix a couple of bugs that may cause replicas to diverge. [#27808](https://github.com/ClickHouse/ClickHouse/pull/27808) ([tavplubix](https://github.com/tavplubix)).
* Fix a rare bug in `DROP PART` which can lead to the error `Unexpected merged part intersects drop range`. [#27807](https://github.com/ClickHouse/ClickHouse/pull/27807) ([alesapin](https://github.com/alesapin)).
* Prevent crashes for some formats when NULL (tombstone) message was coming from Kafka. Closes [#19255](https://github.com/ClickHouse/ClickHouse/issues/19255). [#27794](https://github.com/ClickHouse/ClickHouse/pull/27794) ([filimonov](https://github.com/filimonov)).
* Fix column filtering with union distinct in subquery. Closes [#27578](https://github.com/ClickHouse/ClickHouse/issues/27578). [#27689](https://github.com/ClickHouse/ClickHouse/pull/27689) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix bad type cast when functions like `arrayHas` are applied to arrays of LowCardinality of Nullable of different non-numeric types like `DateTime` and `DateTime64`. In previous versions bad cast occurs. In new version it will lead to exception. This closes [#26330](https://github.com/ClickHouse/ClickHouse/issues/26330). [#27682](https://github.com/ClickHouse/ClickHouse/pull/27682) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix postgresql table function resulting in non-closing connections. Closes [#26088](https://github.com/ClickHouse/ClickHouse/issues/26088). [#27662](https://github.com/ClickHouse/ClickHouse/pull/27662) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fixed another case of `Unexpected merged part ... intersecting drop range ...` error. [#27656](https://github.com/ClickHouse/ClickHouse/pull/27656) ([tavplubix](https://github.com/tavplubix)).
* Fix an error with aliased column in `Distributed` table. [#27652](https://github.com/ClickHouse/ClickHouse/pull/27652) ([Vladimir C](https://github.com/vdimir)).
* After setting `max_memory_usage*` to non-zero value it was not possible to reset it back to 0 (unlimited). It's fixed. [#27638](https://github.com/ClickHouse/ClickHouse/pull/27638) ([tavplubix](https://github.com/tavplubix)).
* Fixed underflow of the time value when constructing it from components. Closes [#27193](https://github.com/ClickHouse/ClickHouse/issues/27193). [#27605](https://github.com/ClickHouse/ClickHouse/pull/27605) ([Vasily Nemkov](https://github.com/Enmk)).
* Fix crash during projection materialization when some parts contain missing columns. This fixes [#27512](https://github.com/ClickHouse/ClickHouse/issues/27512). [#27528](https://github.com/ClickHouse/ClickHouse/pull/27528) ([Amos Bird](https://github.com/amosbird)).
* fix metric `BackgroundMessageBrokerSchedulePoolTask`, maybe mistyped. [#27452](https://github.com/ClickHouse/ClickHouse/pull/27452) ([Ben](https://github.com/benbiti)).
* Fix distributed queries with zero shards and aggregation. [#27427](https://github.com/ClickHouse/ClickHouse/pull/27427) ([Azat Khuzhin](https://github.com/azat)).
* Compatibility when `/proc/meminfo` does not contain KB suffix. [#27361](https://github.com/ClickHouse/ClickHouse/pull/27361) ([Mike Kot](https://github.com/myrrc)).
* Fix incorrect result for query with row-level security, PREWHERE and LowCardinality filter. Fixes [#27179](https://github.com/ClickHouse/ClickHouse/issues/27179). [#27329](https://github.com/ClickHouse/ClickHouse/pull/27329) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed incorrect validation of partition id for MergeTree tables that created with old syntax. [#27328](https://github.com/ClickHouse/ClickHouse/pull/27328) ([tavplubix](https://github.com/tavplubix)).
* Fix MySQL protocol when using parallel formats (CSV / TSV). [#27326](https://github.com/ClickHouse/ClickHouse/pull/27326) ([Raúl Marín](https://github.com/Algunenano)).
* Fix `Cannot find column` error for queries with sampling. Was introduced in [#24574](https://github.com/ClickHouse/ClickHouse/issues/24574). Fixes [#26522](https://github.com/ClickHouse/ClickHouse/issues/26522). [#27301](https://github.com/ClickHouse/ClickHouse/pull/27301) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix errors like `Expected ColumnLowCardinality, gotUInt8` or `Bad cast from type DB::ColumnVector<char8_t> to DB::ColumnLowCardinality` for some queries with `LowCardinality` in `PREWHERE`. And more importantly, fix the lack of whitespace in the error message. Fixes [#23515](https://github.com/ClickHouse/ClickHouse/issues/23515). [#27298](https://github.com/ClickHouse/ClickHouse/pull/27298) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix `distributed_group_by_no_merge = 2` with `distributed_push_down_limit = 1` or `optimize_distributed_group_by_sharding_key = 1` with `LIMIT BY` and `LIMIT OFFSET`. [#27249](https://github.com/ClickHouse/ClickHouse/pull/27249) ([Azat Khuzhin](https://github.com/azat)). These are obscure combination of settings that no one is using.
* Fix mutation stuck on invalid partitions in non-replicated MergeTree. [#27248](https://github.com/ClickHouse/ClickHouse/pull/27248) ([Azat Khuzhin](https://github.com/azat)).
* In case of ambiguity, lambda functions prefer its arguments to other aliases or identifiers. [#27235](https://github.com/ClickHouse/ClickHouse/pull/27235) ([Raúl Marín](https://github.com/Algunenano)).
* Fix column structure in merge join, close [#27091](https://github.com/ClickHouse/ClickHouse/issues/27091). [#27217](https://github.com/ClickHouse/ClickHouse/pull/27217) ([Vladimir C](https://github.com/vdimir)).
* In rare cases `system.detached_parts` table might contain incorrect information for some parts, it's fixed. Fixes [#27114](https://github.com/ClickHouse/ClickHouse/issues/27114). [#27183](https://github.com/ClickHouse/ClickHouse/pull/27183) ([tavplubix](https://github.com/tavplubix)).
* Fix uninitialized memory in functions `multiSearch*` with empty array, close [#27169](https://github.com/ClickHouse/ClickHouse/issues/27169). [#27181](https://github.com/ClickHouse/ClickHouse/pull/27181) ([Vladimir C](https://github.com/vdimir)).
* Fix synchronization in GRPCServer. This PR fixes [#27024](https://github.com/ClickHouse/ClickHouse/issues/27024). [#27064](https://github.com/ClickHouse/ClickHouse/pull/27064) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fixed `cache`, `complex_key_cache`, `ssd_cache`, `complex_key_ssd_cache` configuration parsing. Options `allow_read_expired_keys`, `max_update_queue_size`, `update_queue_push_timeout_milliseconds`, `query_wait_timeout_milliseconds` were not parsed for dictionaries with non `cache` type. [#27032](https://github.com/ClickHouse/ClickHouse/pull/27032) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix possible mutation stack due to race with DROP_RANGE. [#27002](https://github.com/ClickHouse/ClickHouse/pull/27002) ([Azat Khuzhin](https://github.com/azat)).
* Now partition ID in queries like `ALTER TABLE ... PARTITION ID xxx` validates for correctness. Fixes [#25718](https://github.com/ClickHouse/ClickHouse/issues/25718). [#26963](https://github.com/ClickHouse/ClickHouse/pull/26963) ([alesapin](https://github.com/alesapin)).
* Fix "Unknown column name" error with multiple JOINs in some cases, close [#26899](https://github.com/ClickHouse/ClickHouse/issues/26899). [#26957](https://github.com/ClickHouse/ClickHouse/pull/26957) ([Vladimir C](https://github.com/vdimir)).
* Fix reading of custom TLDs (stops processing with lower buffer or bigger file). [#26948](https://github.com/ClickHouse/ClickHouse/pull/26948) ([Azat Khuzhin](https://github.com/azat)).
* Fix error `Missing columns: 'xxx'` when `DEFAULT` column references other non materialized column without `DEFAULT` expression. Fixes [#26591](https://github.com/ClickHouse/ClickHouse/issues/26591). [#26900](https://github.com/ClickHouse/ClickHouse/pull/26900) ([alesapin](https://github.com/alesapin)).
* Fix loading of dictionary keys in `library-bridge` for `library` dictionary source. [#26834](https://github.com/ClickHouse/ClickHouse/pull/26834) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Aggregate function parameters might be lost when applying some combinators causing exceptions like `Conversion from AggregateFunction(topKArray, Array(String)) to AggregateFunction(topKArray(10), Array(String)) is not supported`. It's fixed. Fixes [#26196](https://github.com/ClickHouse/ClickHouse/issues/26196) and [#26433](https://github.com/ClickHouse/ClickHouse/issues/26433). [#26814](https://github.com/ClickHouse/ClickHouse/pull/26814) ([tavplubix](https://github.com/tavplubix)).
* Add `event_time_microseconds` value for `REMOVE_PART` in `system.part_log`. In previous versions is was not set. [#26720](https://github.com/ClickHouse/ClickHouse/pull/26720) ([Azat Khuzhin](https://github.com/azat)).
* Do not remove data on ReplicatedMergeTree table shutdown to avoid creating data to metadata inconsistency. [#26716](https://github.com/ClickHouse/ClickHouse/pull/26716) ([nvartolomei](https://github.com/nvartolomei)).
* Sometimes `SET ROLE` could work incorrectly, this PR fixes that. [#26707](https://github.com/ClickHouse/ClickHouse/pull/26707) ([Vitaly Baranov](https://github.com/vitlibar)).
* Some fixes for parallel formatting (https://github.com/ClickHouse/ClickHouse/issues/26694). [#26703](https://github.com/ClickHouse/ClickHouse/pull/26703) ([Raúl Marín](https://github.com/Algunenano)).
* Fix potential nullptr dereference in window functions. This fixes [#25276](https://github.com/ClickHouse/ClickHouse/issues/25276). [#26668](https://github.com/ClickHouse/ClickHouse/pull/26668) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fix clickhouse-client history file conversion (when upgrading from the format of 3 years old version of clickhouse-client) if file is empty. [#26589](https://github.com/ClickHouse/ClickHouse/pull/26589) ([Azat Khuzhin](https://github.com/azat)).
* Fix incorrect function names of groupBitmapAnd/Or/Xor (can be displayed in some occasions). This fixes. [#26557](https://github.com/ClickHouse/ClickHouse/pull/26557) ([Amos Bird](https://github.com/amosbird)).
* Update `chown` cmd check in clickhouse-server docker entrypoint. It fixes the bug that cluster pod restart failed (or timeout) on kubernetes. [#26545](https://github.com/ClickHouse/ClickHouse/pull/26545) ([Ky Li](https://github.com/Kylinrix)).
* Fix crash in `RabbitMQ` shutdown in case `RabbitMQ` setup was not started. Closes [#26504](https://github.com/ClickHouse/ClickHouse/issues/26504). [#26529](https://github.com/ClickHouse/ClickHouse/pull/26529) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix issues with `CREATE DICTIONARY` query if dictionary name or database name was quoted. Closes [#26491](https://github.com/ClickHouse/ClickHouse/issues/26491). [#26508](https://github.com/ClickHouse/ClickHouse/pull/26508) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix broken column name resolution after rewriting column aliases. This fixes [#26432](https://github.com/ClickHouse/ClickHouse/issues/26432). [#26475](https://github.com/ClickHouse/ClickHouse/pull/26475) ([Amos Bird](https://github.com/amosbird)).
* Fix some fuzzed msan crash. Fixes [#22517](https://github.com/ClickHouse/ClickHouse/issues/22517). [#26428](https://github.com/ClickHouse/ClickHouse/pull/26428) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix infinite non joined block stream in `partial_merge_join` close [#26325](https://github.com/ClickHouse/ClickHouse/issues/26325). [#26374](https://github.com/ClickHouse/ClickHouse/pull/26374) ([Vladimir C](https://github.com/vdimir)).
* Fix possible crash when login as dropped user. This PR fixes [#26073](https://github.com/ClickHouse/ClickHouse/issues/26073). [#26363](https://github.com/ClickHouse/ClickHouse/pull/26363) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix `optimize_distributed_group_by_sharding_key` for multiple columns (leads to incorrect result w/ `optimize_skip_unused_shards=1`/`allow_nondeterministic_optimize_skip_unused_shards=1` and multiple columns in sharding key expression). [#26353](https://github.com/ClickHouse/ClickHouse/pull/26353) ([Azat Khuzhin](https://github.com/azat)).
* Fixed rare bug in lost replica recovery that may cause replicas to diverge. [#26321](https://github.com/ClickHouse/ClickHouse/pull/26321) ([tavplubix](https://github.com/tavplubix)).
* Fix zstd decompression (for import/export in zstd framing format that is unrelated to tables data) in case there are escape sequences at the end of internal buffer. Closes [#26013](https://github.com/ClickHouse/ClickHouse/issues/26013). [#26314](https://github.com/ClickHouse/ClickHouse/pull/26314) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix logical error on join with totals, close [#26017](https://github.com/ClickHouse/ClickHouse/issues/26017). [#26250](https://github.com/ClickHouse/ClickHouse/pull/26250) ([Vladimir C](https://github.com/vdimir)).
* Remove excessive newline in `thread_name` column in `system.stack_trace` table. This fixes [#24124](https://github.com/ClickHouse/ClickHouse/issues/24124). [#26210](https://github.com/ClickHouse/ClickHouse/pull/26210) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix potential crash if more than one `untuple` expression is used. [#26179](https://github.com/ClickHouse/ClickHouse/pull/26179) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Don't throw exception in `toString` for Nullable Enum if Enum does not have a value for zero, close [#25806](https://github.com/ClickHouse/ClickHouse/issues/25806). [#26123](https://github.com/ClickHouse/ClickHouse/pull/26123) ([Vladimir C](https://github.com/vdimir)).
* Fixed incorrect `sequence_id` in MySQL protocol packets that ClickHouse sends on exception during query execution. It might cause MySQL client to reset connection to ClickHouse server. Fixes [#21184](https://github.com/ClickHouse/ClickHouse/issues/21184). [#26051](https://github.com/ClickHouse/ClickHouse/pull/26051) ([tavplubix](https://github.com/tavplubix)).
* Fix for the case that `cutToFirstSignificantSubdomainCustom()`/`cutToFirstSignificantSubdomainCustomWithWWW()`/`firstSignificantSubdomainCustom()` returns incorrect type for consts, and hence `optimize_skip_unused_shards` does not work:. [#26041](https://github.com/ClickHouse/ClickHouse/pull/26041) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible mismatched header when using normal projection with prewhere. This fixes [#26020](https://github.com/ClickHouse/ClickHouse/issues/26020). [#26038](https://github.com/ClickHouse/ClickHouse/pull/26038) ([Amos Bird](https://github.com/amosbird)).
* Fix sharding_key from column w/o function for remote() (before `select * from remote('127.1', system.one, dummy)` leads to `Unknown column: dummy, there are only columns .` error). [#25824](https://github.com/ClickHouse/ClickHouse/pull/25824) ([Azat Khuzhin](https://github.com/azat)).
* Fixed `Not found column ...` and `Missing column ...` errors when selecting from `MaterializeMySQL`. Fixes [#23708](https://github.com/ClickHouse/ClickHouse/issues/23708), [#24830](https://github.com/ClickHouse/ClickHouse/issues/24830), [#25794](https://github.com/ClickHouse/ClickHouse/issues/25794). [#25822](https://github.com/ClickHouse/ClickHouse/pull/25822) ([tavplubix](https://github.com/tavplubix)).
* Fix `optimize_skip_unused_shards_rewrite_in` for non-UInt64 types (may select incorrect shards eventually or throw `Cannot infer type of an empty tuple` or `Function tuple requires at least one argument`). [#25798](https://github.com/ClickHouse/ClickHouse/pull/25798) ([Azat Khuzhin](https://github.com/azat)).
#### Build/Testing/Packaging Improvement
* Now we ran stateful and stateless tests in random timezones. Fixes [#12439](https://github.com/ClickHouse/ClickHouse/issues/12439). Reading String as DateTime and writing DateTime as String in Protobuf format now respect timezone. Reading UInt16 as DateTime in Arrow and Parquet formats now treat it as Date and then converts to DateTime with respect to DateTime's timezone, because Date is serialized in Arrow and Parquet as UInt16. GraphiteMergeTree now respect time zone for rounding of times. Fixes [#5098](https://github.com/ClickHouse/ClickHouse/issues/5098). Author: @alexey-milovidov. [#15408](https://github.com/ClickHouse/ClickHouse/pull/15408) ([alesapin](https://github.com/alesapin)).
* `clickhouse-test` supports SQL tests with [Jinja2](https://jinja.palletsprojects.com/en/3.0.x/templates/#synopsis) templates. [#26579](https://github.com/ClickHouse/ClickHouse/pull/26579) ([Vladimir C](https://github.com/vdimir)).
* Add support for build with `clang-13`. This closes [#27705](https://github.com/ClickHouse/ClickHouse/issues/27705). [#27714](https://github.com/ClickHouse/ClickHouse/pull/27714) ([alexey-milovidov](https://github.com/alexey-milovidov)). [#27777](https://github.com/ClickHouse/ClickHouse/pull/27777) ([Sergei Semin](https://github.com/syominsergey))
* Add CMake options to build with or without specific CPU instruction set. This is for [#17469](https://github.com/ClickHouse/ClickHouse/issues/17469) and [#27509](https://github.com/ClickHouse/ClickHouse/issues/27509). [#27508](https://github.com/ClickHouse/ClickHouse/pull/27508) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix linking of auxiliar programs when using dynamic libraries. [#26958](https://github.com/ClickHouse/ClickHouse/pull/26958) ([Raúl Marín](https://github.com/Algunenano)).
* Update RocksDB to `2021-07-16` master. [#26411](https://github.com/ClickHouse/ClickHouse/pull/26411) ([alexey-milovidov](https://github.com/alexey-milovidov)).
### ClickHouse release v21.8, 2021-08-12
#### Upgrade Notes
* New version is using `Map` data type for system logs tables (`system.query_log`, `system.query_thread_log`, `system.processes`, `system.opentelemetry_span_log`). These tables will be auto-created with new data types. Virtual columns are created to support old queries. Closes [#18698](https://github.com/ClickHouse/ClickHouse/issues/18698). [#23934](https://github.com/ClickHouse/ClickHouse/pull/23934), [#25773](https://github.com/ClickHouse/ClickHouse/pull/25773) ([hexiaoting](https://github.com/hexiaoting), [sundy-li](https://github.com/sundy-li), [Maksim Kita](https://github.com/kitaisreal)). If you want to *downgrade* from version 21.8 to older versions, you will need to cleanup system tables with logs manually. Look at `/var/lib/clickhouse/data/system/*_log`.
#### New Features
* Add support for a part of SQL/JSON standard. [#24148](https://github.com/ClickHouse/ClickHouse/pull/24148) ([l1tsolaiki](https://github.com/l1tsolaiki), [Kseniia Sumarokova](https://github.com/kssenii)).
* Collect common system metrics (in `system.asynchronous_metrics` and `system.asynchronous_metric_log`) on CPU usage, disk usage, memory usage, IO, network, files, load average, CPU frequencies, thermal sensors, EDAC counters, system uptime; also added metrics about the scheduling jitter and the time spent collecting the metrics. It works similar to `atop` in ClickHouse and allows access to monitoring data even if you have no additional tools installed. Close [#9430](https://github.com/ClickHouse/ClickHouse/issues/9430). [#24416](https://github.com/ClickHouse/ClickHouse/pull/24416) ([alexey-milovidov](https://github.com/alexey-milovidov), [Yegor Levankov](https://github.com/elevankoff)).
* Add MaterializedPostgreSQL table engine and database engine. This database engine allows replicating a whole database or any subset of database tables. [#20470](https://github.com/ClickHouse/ClickHouse/pull/20470) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add new functions `leftPad()`, `rightPad()`, `leftPadUTF8()`, `rightPadUTF8()`. [#26075](https://github.com/ClickHouse/ClickHouse/pull/26075) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add the `FIRST` keyword to the `ADD INDEX` command to be able to add the index at the beginning of the indices list. [#25904](https://github.com/ClickHouse/ClickHouse/pull/25904) ([xjewer](https://github.com/xjewer)).
* Introduce `system.data_skipping_indices` table containing information about existing data skipping indices. Close [#7659](https://github.com/ClickHouse/ClickHouse/issues/7659). [#25693](https://github.com/ClickHouse/ClickHouse/pull/25693) ([Dmitry Novik](https://github.com/novikd)).
* Add `bin`/`unbin` functions. [#25609](https://github.com/ClickHouse/ClickHouse/pull/25609) ([zhaoyu](https://github.com/zxc111)).
* Support `Map` and `UInt128`, `Int128`, `UInt256`, `Int256` types in `mapAdd` and `mapSubtract` functions. [#25596](https://github.com/ClickHouse/ClickHouse/pull/25596) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Support `DISTINCT ON (columns)` expression, close [#25404](https://github.com/ClickHouse/ClickHouse/issues/25404). [#25589](https://github.com/ClickHouse/ClickHouse/pull/25589) ([Zijie Lu](https://github.com/TszKitLo40)).
* Add an ability to reset a custom setting to default and remove it from the table's metadata. It allows rolling back the change without knowing the system/config's default. Closes [#14449](https://github.com/ClickHouse/ClickHouse/issues/14449). [#17769](https://github.com/ClickHouse/ClickHouse/pull/17769) ([xjewer](https://github.com/xjewer)).
* Render pipelines as graphs in Web UI if `EXPLAIN PIPELINE graph = 1` query is submitted. [#26067](https://github.com/ClickHouse/ClickHouse/pull/26067) ([alexey-milovidov](https://github.com/alexey-milovidov)).
#### Performance Improvements
* Compile aggregate functions. Use option `compile_aggregate_expressions` to enable it. [#24789](https://github.com/ClickHouse/ClickHouse/pull/24789) ([Maksim Kita](https://github.com/kitaisreal)).
* Improve latency of short queries that require reading from tables with many columns. [#26371](https://github.com/ClickHouse/ClickHouse/pull/26371) ([Anton Popov](https://github.com/CurtizJ)).
#### Improvements
* Use `Map` data type for system logs tables (`system.query_log`, `system.query_thread_log`, `system.processes`, `system.opentelemetry_span_log`). These tables will be auto-created with new data types. Virtual columns are created to support old queries. Closes [#18698](https://github.com/ClickHouse/ClickHouse/issues/18698). [#23934](https://github.com/ClickHouse/ClickHouse/pull/23934), [#25773](https://github.com/ClickHouse/ClickHouse/pull/25773) ([hexiaoting](https://github.com/hexiaoting), [sundy-li](https://github.com/sundy-li), [Maksim Kita](https://github.com/kitaisreal)).
* For a dictionary with a complex key containing only one attribute, allow not wrapping the key expression in tuple for functions `dictGet`, `dictHas`. [#26130](https://github.com/ClickHouse/ClickHouse/pull/26130) ([Maksim Kita](https://github.com/kitaisreal)).
* Implement function `bin`/`hex` from `AggregateFunction` states. [#26094](https://github.com/ClickHouse/ClickHouse/pull/26094) ([zhaoyu](https://github.com/zxc111)).
* Support arguments of `UUID` type for `empty` and `notEmpty` functions. `UUID` is empty if it is all zeros (nil UUID). Closes [#3446](https://github.com/ClickHouse/ClickHouse/issues/3446). [#25974](https://github.com/ClickHouse/ClickHouse/pull/25974) ([zhaoyu](https://github.com/zxc111)).
* Add support for `SET SQL_SELECT_LIMIT` in MySQL protocol. Closes [#17115](https://github.com/ClickHouse/ClickHouse/issues/17115). [#25972](https://github.com/ClickHouse/ClickHouse/pull/25972) ([Kseniia Sumarokova](https://github.com/kssenii)).
* More instrumentation for network interaction: add counters for recv/send bytes; add gauges for recvs/sends. Added missing documentation. Close [#5897](https://github.com/ClickHouse/ClickHouse/issues/5897). [#25962](https://github.com/ClickHouse/ClickHouse/pull/25962) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add setting `optimize_move_to_prewhere_if_final`. If query has `FINAL`, the optimization `move_to_prewhere` will be enabled only if both `optimize_move_to_prewhere` and `optimize_move_to_prewhere_if_final` are enabled. Closes [#8684](https://github.com/ClickHouse/ClickHouse/issues/8684). [#25940](https://github.com/ClickHouse/ClickHouse/pull/25940) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Allow complex quoted identifiers of JOINed tables. Close [#17861](https://github.com/ClickHouse/ClickHouse/issues/17861). [#25924](https://github.com/ClickHouse/ClickHouse/pull/25924) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add support for Unicode (e.g. Chinese, Cyrillic) components in `Nested` data types. Close [#25594](https://github.com/ClickHouse/ClickHouse/issues/25594). [#25923](https://github.com/ClickHouse/ClickHouse/pull/25923) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow `quantiles*` functions to work with `aggregate_functions_null_for_empty`. Close [#25892](https://github.com/ClickHouse/ClickHouse/issues/25892). [#25919](https://github.com/ClickHouse/ClickHouse/pull/25919) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow parameters for parametric aggregate functions to be arbitrary constant expressions (e.g., `1 + 2`), not just literals. It also allows using the query parameters (in parameterized queries like `{param:UInt8}`) inside parametric aggregate functions. Closes [#11607](https://github.com/ClickHouse/ClickHouse/issues/11607). [#25910](https://github.com/ClickHouse/ClickHouse/pull/25910) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Correctly throw the exception on the attempt to parse an invalid `Date`. Closes [#6481](https://github.com/ClickHouse/ClickHouse/issues/6481). [#25909](https://github.com/ClickHouse/ClickHouse/pull/25909) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support for multiple includes in configuration. It is possible to include users configuration, remote server configuration from multiple sources. Simply place `<include />` element with `from_zk`, `from_env` or `incl` attribute, and it will be replaced with the substitution. [#24404](https://github.com/ClickHouse/ClickHouse/pull/24404) ([nvartolomei](https://github.com/nvartolomei)).
* Support for queries with a column named `"null"` (it must be specified in back-ticks or double quotes) and `ON CLUSTER`. Closes [#24035](https://github.com/ClickHouse/ClickHouse/issues/24035). [#25907](https://github.com/ClickHouse/ClickHouse/pull/25907) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support `LowCardinality`, `Decimal`, and `UUID` for `JSONExtract`. Closes [#24606](https://github.com/ClickHouse/ClickHouse/issues/24606). [#25900](https://github.com/ClickHouse/ClickHouse/pull/25900) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Convert history file from `readline` format to `replxx` format. [#25888](https://github.com/ClickHouse/ClickHouse/pull/25888) ([Azat Khuzhin](https://github.com/azat)).
* Fix an issue which can lead to intersecting parts after `DROP PART` or background deletion of an empty part. [#25884](https://github.com/ClickHouse/ClickHouse/pull/25884) ([alesapin](https://github.com/alesapin)).
* Better handling of lost parts for `ReplicatedMergeTree` tables. Fixes rare inconsistencies in `ReplicationQueue`. Fixes [#10368](https://github.com/ClickHouse/ClickHouse/issues/10368). [#25820](https://github.com/ClickHouse/ClickHouse/pull/25820) ([alesapin](https://github.com/alesapin)).
* Allow starting clickhouse-client with unreadable working directory. [#25817](https://github.com/ClickHouse/ClickHouse/pull/25817) ([ianton-ru](https://github.com/ianton-ru)).
* Fix "No available columns" error for `Merge` storage. [#25801](https://github.com/ClickHouse/ClickHouse/pull/25801) ([Azat Khuzhin](https://github.com/azat)).
* MySQL Engine now supports the exchange of column comments between MySQL and ClickHouse. [#25795](https://github.com/ClickHouse/ClickHouse/pull/25795) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
* Fix inconsistent behaviour of `GROUP BY` constant on empty set. Closes [#6842](https://github.com/ClickHouse/ClickHouse/issues/6842). [#25786](https://github.com/ClickHouse/ClickHouse/pull/25786) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Cancel already running merges in partition on `DROP PARTITION` and `TRUNCATE` for `ReplicatedMergeTree`. Resolves [#17151](https://github.com/ClickHouse/ClickHouse/issues/17151). [#25684](https://github.com/ClickHouse/ClickHouse/pull/25684) ([tavplubix](https://github.com/tavplubix)).
* Support ENUM` data type for MaterializeMySQL. [#25676](https://github.com/ClickHouse/ClickHouse/pull/25676) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
* Support materialized and aliased columns in JOIN, close [#13274](https://github.com/ClickHouse/ClickHouse/issues/13274). [#25634](https://github.com/ClickHouse/ClickHouse/pull/25634) ([Vladimir C](https://github.com/vdimir)).
* Fix possible logical race condition between `ALTER TABLE ... DETACH` and background merges. [#25605](https://github.com/ClickHouse/ClickHouse/pull/25605) ([Azat Khuzhin](https://github.com/azat)).
* Make `NetworkReceiveElapsedMicroseconds` metric to correctly include the time spent waiting for data from the client to `INSERT`. Close [#9958](https://github.com/ClickHouse/ClickHouse/issues/9958). [#25602](https://github.com/ClickHouse/ClickHouse/pull/25602) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support `TRUNCATE TABLE` for S3 and HDFS. Close [#25530](https://github.com/ClickHouse/ClickHouse/issues/25530). [#25550](https://github.com/ClickHouse/ClickHouse/pull/25550) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Support for dynamic reloading of config to change number of threads in pool for background jobs execution (merges, mutations, fetches). [#25548](https://github.com/ClickHouse/ClickHouse/pull/25548) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow extracting of non-string element as string using `JSONExtract`. This is for [#25414](https://github.com/ClickHouse/ClickHouse/issues/25414). [#25452](https://github.com/ClickHouse/ClickHouse/pull/25452) ([Amos Bird](https://github.com/amosbird)).
* Support regular expression in `Database` argument for `StorageMerge`. Close [#776](https://github.com/ClickHouse/ClickHouse/issues/776). [#25064](https://github.com/ClickHouse/ClickHouse/pull/25064) ([flynn](https://github.com/ucasfl)).
* Web UI: if the value looks like a URL, automatically generate a link. [#25965](https://github.com/ClickHouse/ClickHouse/pull/25965) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make `sudo service clickhouse-server start` to work on systems with `systemd` like Centos 8. Close [#14298](https://github.com/ClickHouse/ClickHouse/issues/14298). Close [#17799](https://github.com/ClickHouse/ClickHouse/issues/17799). [#25921](https://github.com/ClickHouse/ClickHouse/pull/25921) ([alexey-milovidov](https://github.com/alexey-milovidov)).
#### Bug Fixes
* Fix incorrect `SET ROLE` in some cases. [#26707](https://github.com/ClickHouse/ClickHouse/pull/26707) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix potential `nullptr` dereference in window functions. Fix [#25276](https://github.com/ClickHouse/ClickHouse/issues/25276). [#26668](https://github.com/ClickHouse/ClickHouse/pull/26668) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Fix incorrect function names of `groupBitmapAnd/Or/Xor`. Fix [#26557](https://github.com/ClickHouse/ClickHouse/pull/26557) ([Amos Bird](https://github.com/amosbird)).
* Fix crash in RabbitMQ shutdown in case RabbitMQ setup was not started. Closes [#26504](https://github.com/ClickHouse/ClickHouse/issues/26504). [#26529](https://github.com/ClickHouse/ClickHouse/pull/26529) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix issues with `CREATE DICTIONARY` query if dictionary name or database name was quoted. Closes [#26491](https://github.com/ClickHouse/ClickHouse/issues/26491). [#26508](https://github.com/ClickHouse/ClickHouse/pull/26508) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix broken name resolution after rewriting column aliases. Fix [#26432](https://github.com/ClickHouse/ClickHouse/issues/26432). [#26475](https://github.com/ClickHouse/ClickHouse/pull/26475) ([Amos Bird](https://github.com/amosbird)).
* Fix infinite non-joined block stream in `partial_merge_join` close [#26325](https://github.com/ClickHouse/ClickHouse/issues/26325). [#26374](https://github.com/ClickHouse/ClickHouse/pull/26374) ([Vladimir C](https://github.com/vdimir)).
* Fix possible crash when login as dropped user. Fix [#26073](https://github.com/ClickHouse/ClickHouse/issues/26073). [#26363](https://github.com/ClickHouse/ClickHouse/pull/26363) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix `optimize_distributed_group_by_sharding_key` for multiple columns (leads to incorrect result w/ `optimize_skip_unused_shards=1`/`allow_nondeterministic_optimize_skip_unused_shards=1` and multiple columns in sharding key expression). [#26353](https://github.com/ClickHouse/ClickHouse/pull/26353) ([Azat Khuzhin](https://github.com/azat)).
* `CAST` from `Date` to `DateTime` (or `DateTime64`) was not using the timezone of the `DateTime` type. It can also affect the comparison between `Date` and `DateTime`. Inference of the common type for `Date` and `DateTime` also was not using the corresponding timezone. It affected the results of function `if` and array construction. Closes [#24128](https://github.com/ClickHouse/ClickHouse/issues/24128). [#24129](https://github.com/ClickHouse/ClickHouse/pull/24129) ([Maksim Kita](https://github.com/kitaisreal)).
* Fixed rare bug in lost replica recovery that may cause replicas to diverge. [#26321](https://github.com/ClickHouse/ClickHouse/pull/26321) ([tavplubix](https://github.com/tavplubix)).
* Fix zstd decompression in case there are escape sequences at the end of internal buffer. Closes [#26013](https://github.com/ClickHouse/ClickHouse/issues/26013). [#26314](https://github.com/ClickHouse/ClickHouse/pull/26314) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix logical error on join with totals, close [#26017](https://github.com/ClickHouse/ClickHouse/issues/26017). [#26250](https://github.com/ClickHouse/ClickHouse/pull/26250) ([Vladimir C](https://github.com/vdimir)).
* Remove excessive newline in `thread_name` column in `system.stack_trace` table. Fix [#24124](https://github.com/ClickHouse/ClickHouse/issues/24124). [#26210](https://github.com/ClickHouse/ClickHouse/pull/26210) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `joinGet` with `LowCarinality` columns, close [#25993](https://github.com/ClickHouse/ClickHouse/issues/25993). [#26118](https://github.com/ClickHouse/ClickHouse/pull/26118) ([Vladimir C](https://github.com/vdimir)).
* Fix possible crash in `pointInPolygon` if the setting `validate_polygons` is turned off. [#26113](https://github.com/ClickHouse/ClickHouse/pull/26113) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix throwing exception when iterate over non-existing remote directory. [#26087](https://github.com/ClickHouse/ClickHouse/pull/26087) ([ianton-ru](https://github.com/ianton-ru)).
* Fix rare server crash because of `abort` in ZooKeeper client. Fixes [#25813](https://github.com/ClickHouse/ClickHouse/issues/25813). [#26079](https://github.com/ClickHouse/ClickHouse/pull/26079) ([alesapin](https://github.com/alesapin)).
* Fix wrong thread count estimation for right subquery join in some cases. Close [#24075](https://github.com/ClickHouse/ClickHouse/issues/24075). [#26052](https://github.com/ClickHouse/ClickHouse/pull/26052) ([Vladimir C](https://github.com/vdimir)).
* Fixed incorrect `sequence_id` in MySQL protocol packets that ClickHouse sends on exception during query execution. It might cause MySQL client to reset connection to ClickHouse server. Fixes [#21184](https://github.com/ClickHouse/ClickHouse/issues/21184). [#26051](https://github.com/ClickHouse/ClickHouse/pull/26051) ([tavplubix](https://github.com/tavplubix)).
* Fix possible mismatched header when using normal projection with `PREWHERE`. Fix [#26020](https://github.com/ClickHouse/ClickHouse/issues/26020). [#26038](https://github.com/ClickHouse/ClickHouse/pull/26038) ([Amos Bird](https://github.com/amosbird)).
* Fix formatting of type `Map` with integer keys to `JSON`. [#25982](https://github.com/ClickHouse/ClickHouse/pull/25982) ([Anton Popov](https://github.com/CurtizJ)).
* Fix possible deadlock during query profiler stack unwinding. Fix [#25968](https://github.com/ClickHouse/ClickHouse/issues/25968). [#25970](https://github.com/ClickHouse/ClickHouse/pull/25970) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix crash on call `dictGet()` with bad arguments. [#25913](https://github.com/ClickHouse/ClickHouse/pull/25913) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fixed `scram-sha-256` authentication for PostgreSQL engines. Closes [#24516](https://github.com/ClickHouse/ClickHouse/issues/24516). [#25906](https://github.com/ClickHouse/ClickHouse/pull/25906) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix extremely long backoff for background tasks when the background pool is full. Fixes [#25836](https://github.com/ClickHouse/ClickHouse/issues/25836). [#25893](https://github.com/ClickHouse/ClickHouse/pull/25893) ([alesapin](https://github.com/alesapin)).
* Fix ARM exception handling with non default page size. Fixes [#25512](https://github.com/ClickHouse/ClickHouse/issues/25512), [#25044](https://github.com/ClickHouse/ClickHouse/issues/25044), [#24901](https://github.com/ClickHouse/ClickHouse/issues/24901), [#23183](https://github.com/ClickHouse/ClickHouse/issues/23183), [#20221](https://github.com/ClickHouse/ClickHouse/issues/20221), [#19703](https://github.com/ClickHouse/ClickHouse/issues/19703), [#19028](https://github.com/ClickHouse/ClickHouse/issues/19028), [#18391](https://github.com/ClickHouse/ClickHouse/issues/18391), [#18121](https://github.com/ClickHouse/ClickHouse/issues/18121), [#17994](https://github.com/ClickHouse/ClickHouse/issues/17994), [#12483](https://github.com/ClickHouse/ClickHouse/issues/12483). [#25854](https://github.com/ClickHouse/ClickHouse/pull/25854) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix sharding_key from column w/o function for `remote()` (before `select * from remote('127.1', system.one, dummy)` leads to `Unknown column: dummy, there are only columns .` error). [#25824](https://github.com/ClickHouse/ClickHouse/pull/25824) ([Azat Khuzhin](https://github.com/azat)).
* Fixed `Not found column ...` and `Missing column ...` errors when selecting from `MaterializeMySQL`. Fixes [#23708](https://github.com/ClickHouse/ClickHouse/issues/23708), [#24830](https://github.com/ClickHouse/ClickHouse/issues/24830), [#25794](https://github.com/ClickHouse/ClickHouse/issues/25794). [#25822](https://github.com/ClickHouse/ClickHouse/pull/25822) ([tavplubix](https://github.com/tavplubix)).
* Fix `optimize_skip_unused_shards_rewrite_in` for non-UInt64 types (may select incorrect shards eventually or throw `Cannot infer type of an empty tuple` or `Function tuple requires at least one argument`). [#25798](https://github.com/ClickHouse/ClickHouse/pull/25798) ([Azat Khuzhin](https://github.com/azat)).
* Fix rare bug with `DROP PART` query for `ReplicatedMergeTree` tables which can lead to error message `Unexpected merged part intersecting drop range`. [#25783](https://github.com/ClickHouse/ClickHouse/pull/25783) ([alesapin](https://github.com/alesapin)).
* Fix bug in `TTL` with `GROUP BY` expression which refuses to execute `TTL` after first execution in part. [#25743](https://github.com/ClickHouse/ClickHouse/pull/25743) ([alesapin](https://github.com/alesapin)).
* Allow StorageMerge to access tables with aliases. Closes [#6051](https://github.com/ClickHouse/ClickHouse/issues/6051). [#25694](https://github.com/ClickHouse/ClickHouse/pull/25694) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix slow dict join in some cases, close [#24209](https://github.com/ClickHouse/ClickHouse/issues/24209). [#25618](https://github.com/ClickHouse/ClickHouse/pull/25618) ([Vladimir C](https://github.com/vdimir)).
* Fix `ALTER MODIFY COLUMN` of columns, which participates in TTL expressions. [#25554](https://github.com/ClickHouse/ClickHouse/pull/25554) ([Anton Popov](https://github.com/CurtizJ)).
* Fix assertion in `PREWHERE` with non-UInt8 type, close [#19589](https://github.com/ClickHouse/ClickHouse/issues/19589). [#25484](https://github.com/ClickHouse/ClickHouse/pull/25484) ([Vladimir C](https://github.com/vdimir)).
* Fix some fuzzed msan crash. Fixes [#22517](https://github.com/ClickHouse/ClickHouse/issues/22517). [#26428](https://github.com/ClickHouse/ClickHouse/pull/26428) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Update `chown` cmd check in `clickhouse-server` docker entrypoint. It fixes error 'cluster pod restart failed (or timeout)' on kubernetes. [#26545](https://github.com/ClickHouse/ClickHouse/pull/26545) ([Ky Li](https://github.com/Kylinrix)).
### ClickHouse release v21.7, 2021-07-09
#### Backward Incompatible Change
* Improved performance of queries with explicitly defined large sets. Added compatibility setting `legacy_column_name_of_tuple_literal`. It makes sense to set it to `true`, while doing rolling update of cluster from version lower than 21.7 to any higher version. Otherwise distributed queries with explicitly defined sets at `IN` clause may fail during update. [#25371](https://github.com/ClickHouse/ClickHouse/pull/25371) ([Anton Popov](https://github.com/CurtizJ)).
* Forward/backward incompatible change of maximum buffer size in clickhouse-keeper (an experimental alternative to ZooKeeper). Better to do it now (before production), than later. [#25421](https://github.com/ClickHouse/ClickHouse/pull/25421) ([alesapin](https://github.com/alesapin)).
#### New Feature
* Support configuration in YAML format as alternative to XML. This closes [#3607](https://github.com/ClickHouse/ClickHouse/issues/3607). [#21858](https://github.com/ClickHouse/ClickHouse/pull/21858) ([BoloniniD](https://github.com/BoloniniD)).
* Provides a way to restore replicated table when the data is (possibly) present, but the ZooKeeper metadata is lost. Resolves [#13458](https://github.com/ClickHouse/ClickHouse/issues/13458). [#13652](https://github.com/ClickHouse/ClickHouse/pull/13652) ([Mike Kot](https://github.com/myrrc)).
* Support structs and maps in Arrow/Parquet/ORC and dictionaries in Arrow input/output formats. Present new setting `output_format_arrow_low_cardinality_as_dictionary`. [#24341](https://github.com/ClickHouse/ClickHouse/pull/24341) ([Kruglov Pavel](https://github.com/Avogar)).
* Added support for `Array` type in dictionaries. [#25119](https://github.com/ClickHouse/ClickHouse/pull/25119) ([Maksim Kita](https://github.com/kitaisreal)).
* Added function `bitPositionsToArray`. Closes [#23792](https://github.com/ClickHouse/ClickHouse/issues/23792). Author [Kevin Wan] (@MaxWk). [#25394](https://github.com/ClickHouse/ClickHouse/pull/25394) ([Maksim Kita](https://github.com/kitaisreal)).
* Added function `dateName` to return names like 'Friday' or 'April'. Author [Daniil Kondratyev] (@dankondr). [#25372](https://github.com/ClickHouse/ClickHouse/pull/25372) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `toJSONString` function to serialize columns to their JSON representations. [#25164](https://github.com/ClickHouse/ClickHouse/pull/25164) ([Amos Bird](https://github.com/amosbird)).
* Now `query_log` has two new columns: `initial_query_start_time`, `initial_query_start_time_microsecond` that record the starting time of a distributed query if any. [#25022](https://github.com/ClickHouse/ClickHouse/pull/25022) ([Amos Bird](https://github.com/amosbird)).
* Add aggregate function `segmentLengthSum`. [#24250](https://github.com/ClickHouse/ClickHouse/pull/24250) ([flynn](https://github.com/ucasfl)).
* Add a new boolean setting `prefer_global_in_and_join` which defaults all IN/JOIN as GLOBAL IN/JOIN. [#23434](https://github.com/ClickHouse/ClickHouse/pull/23434) ([Amos Bird](https://github.com/amosbird)).
* Support `ALTER DELETE` queries for `Join` table engine. [#23260](https://github.com/ClickHouse/ClickHouse/pull/23260) ([foolchi](https://github.com/foolchi)).
* Add `quantileBFloat16` aggregate function as well as the corresponding `quantilesBFloat16` and `medianBFloat16`. It is very simple and fast quantile estimator with relative error not more than 0.390625%. This closes [#16641](https://github.com/ClickHouse/ClickHouse/issues/16641). [#23204](https://github.com/ClickHouse/ClickHouse/pull/23204) ([Ivan Novitskiy](https://github.com/RedClusive)).
* Implement `sequenceNextNode()` function useful for `flow analysis`. [#19766](https://github.com/ClickHouse/ClickHouse/pull/19766) ([achimbab](https://github.com/achimbab)).
#### Experimental Feature
* Add support for virtual filesystem over HDFS. [#11058](https://github.com/ClickHouse/ClickHouse/pull/11058) ([overshov](https://github.com/overshov)) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Now clickhouse-keeper (an experimental alternative to ZooKeeper) supports ZooKeeper-like `digest` ACLs. [#24448](https://github.com/ClickHouse/ClickHouse/pull/24448) ([alesapin](https://github.com/alesapin)).
#### Performance Improvement
* Added optimization that transforms some functions to reading of subcolumns to reduce amount of read data. E.g., statement `col IS NULL` is transformed to reading of subcolumn `col.null`. Optimization can be enabled by setting `optimize_functions_to_subcolumns` which is currently off by default. [#24406](https://github.com/ClickHouse/ClickHouse/pull/24406) ([Anton Popov](https://github.com/CurtizJ)).
* Rewrite more columns to possible alias expressions. This may enable better optimization, such as projections. [#24405](https://github.com/ClickHouse/ClickHouse/pull/24405) ([Amos Bird](https://github.com/amosbird)).
* Index of type `bloom_filter` can be used for expressions with `hasAny` function with constant arrays. This closes: [#24291](https://github.com/ClickHouse/ClickHouse/issues/24291). [#24900](https://github.com/ClickHouse/ClickHouse/pull/24900) ([Vasily Nemkov](https://github.com/Enmk)).
* Add exponential backoff to reschedule read attempt in case RabbitMQ queues are empty. (ClickHouse has support for importing data from RabbitMQ). Closes [#24340](https://github.com/ClickHouse/ClickHouse/issues/24340). [#24415](https://github.com/ClickHouse/ClickHouse/pull/24415) ([Kseniia Sumarokova](https://github.com/kssenii)).
#### Improvement
* Allow to limit bandwidth for replication. Add two Replicated\*MergeTree settings: `max_replicated_fetches_network_bandwidth` and `max_replicated_sends_network_bandwidth` which allows to limit maximum speed of replicated fetches/sends for table. Add two server-wide settings (in `default` user profile): `max_replicated_fetches_network_bandwidth_for_server` and `max_replicated_sends_network_bandwidth_for_server` which limit maximum speed of replication for all tables. The settings are not followed perfectly accurately. Turned off by default. Fixes [#1821](https://github.com/ClickHouse/ClickHouse/issues/1821). [#24573](https://github.com/ClickHouse/ClickHouse/pull/24573) ([alesapin](https://github.com/alesapin)).
* Resource constraints and isolation for ODBC and Library bridges. Use separate `clickhouse-bridge` group and user for bridge processes. Set oom_score_adj so the bridges will be first subjects for OOM killer. Set set maximum RSS to 1 GiB. Closes [#23861](https://github.com/ClickHouse/ClickHouse/issues/23861). [#25280](https://github.com/ClickHouse/ClickHouse/pull/25280) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add standalone `clickhouse-keeper` symlink to the main `clickhouse` binary. Now it's possible to run coordination without the main clickhouse server. [#24059](https://github.com/ClickHouse/ClickHouse/pull/24059) ([alesapin](https://github.com/alesapin)).
* Use global settings for query to `VIEW`. Fixed the behavior when queries to `VIEW` use local settings, that leads to errors if setting on `CREATE VIEW` and `SELECT` were different. As for now, `VIEW` won't use these modified settings, but you can still pass additional settings in `SETTINGS` section of `CREATE VIEW` query. Close [#20551](https://github.com/ClickHouse/ClickHouse/issues/20551). [#24095](https://github.com/ClickHouse/ClickHouse/pull/24095) ([Vladimir](https://github.com/vdimir)).
* On server start, parts with incorrect partition ID would not be ever removed, but always detached. [#25070](https://github.com/ClickHouse/ClickHouse/issues/25070). [#25166](https://github.com/ClickHouse/ClickHouse/pull/25166) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Increase size of background schedule pool to 128 (`background_schedule_pool_size` setting). It allows avoiding replication queue hung on slow zookeeper connection. [#25072](https://github.com/ClickHouse/ClickHouse/pull/25072) ([alesapin](https://github.com/alesapin)).
* Add merge tree setting `max_parts_to_merge_at_once` which limits the number of parts that can be merged in the background at once. Doesn't affect `OPTIMIZE FINAL` query. Fixes [#1820](https://github.com/ClickHouse/ClickHouse/issues/1820). [#24496](https://github.com/ClickHouse/ClickHouse/pull/24496) ([alesapin](https://github.com/alesapin)).
* Allow `NOT IN` operator to be used in partition pruning. [#24894](https://github.com/ClickHouse/ClickHouse/pull/24894) ([Amos Bird](https://github.com/amosbird)).
* Recognize IPv4 addresses like `127.0.1.1` as local. This is controversial and closes [#23504](https://github.com/ClickHouse/ClickHouse/issues/23504). Michael Filimonov will test this feature. [#24316](https://github.com/ClickHouse/ClickHouse/pull/24316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* ClickHouse database created with MaterializeMySQL (it is an experimental feature) now contains all column comments from the MySQL database that materialized. [#25199](https://github.com/ClickHouse/ClickHouse/pull/25199) ([Storozhuk Kostiantyn](https://github.com/sand6255)).
* Add settings (`connection_auto_close`/`connection_max_tries`/`connection_pool_size`) for MySQL storage engine. [#24146](https://github.com/ClickHouse/ClickHouse/pull/24146) ([Azat Khuzhin](https://github.com/azat)).
* Improve startup time of Distributed engine. [#25663](https://github.com/ClickHouse/ClickHouse/pull/25663) ([Azat Khuzhin](https://github.com/azat)).
* Improvement for Distributed tables. Drop replicas from dirname for internal_replication=true (allows INSERT into Distributed with cluster from any number of replicas, before only 15 replicas was supported, everything more will fail with ENAMETOOLONG while creating directory for async blocks). [#25513](https://github.com/ClickHouse/ClickHouse/pull/25513) ([Azat Khuzhin](https://github.com/azat)).
* Added support `Interval` type for `LowCardinality`. It is needed for intermediate values of some expressions. Closes [#21730](https://github.com/ClickHouse/ClickHouse/issues/21730). [#25410](https://github.com/ClickHouse/ClickHouse/pull/25410) ([Vladimir](https://github.com/vdimir)).
* Add `==` operator on time conditions for `sequenceMatch` and `sequenceCount` functions. For eg: sequenceMatch('(?1)(?t==1)(?2)')(time, data = 1, data = 2). [#25299](https://github.com/ClickHouse/ClickHouse/pull/25299) ([Christophe Kalenzaga](https://github.com/mga-chka)).
* Add settings `http_max_fields`, `http_max_field_name_size`, `http_max_field_value_size`. [#25296](https://github.com/ClickHouse/ClickHouse/pull/25296) ([Ivan](https://github.com/abyss7)).
* Add support for function `if` with `Decimal` and `Int` types on its branches. This closes [#20549](https://github.com/ClickHouse/ClickHouse/issues/20549). This closes [#10142](https://github.com/ClickHouse/ClickHouse/issues/10142). [#25283](https://github.com/ClickHouse/ClickHouse/pull/25283) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Update prompt in `clickhouse-client` and display a message when reconnecting. This closes [#10577](https://github.com/ClickHouse/ClickHouse/issues/10577). [#25281](https://github.com/ClickHouse/ClickHouse/pull/25281) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Correct memory tracking in aggregate function `topK`. This closes [#25259](https://github.com/ClickHouse/ClickHouse/issues/25259). [#25260](https://github.com/ClickHouse/ClickHouse/pull/25260) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `topLevelDomain` for IDN hosts (i.e. `example.рф`), before it returns empty string for such hosts. [#25103](https://github.com/ClickHouse/ClickHouse/pull/25103) ([Azat Khuzhin](https://github.com/azat)).
* Detect Linux kernel version at runtime (for worked nested epoll, that is required for `async_socket_for_remote`/`use_hedged_requests`, otherwise remote queries may stuck). [#25067](https://github.com/ClickHouse/ClickHouse/pull/25067) ([Azat Khuzhin](https://github.com/azat)).
* For distributed query, when `optimize_skip_unused_shards=1`, allow to skip shard with condition like `(sharding key) IN (one-element-tuple)`. (Tuples with many elements were supported. Tuple with single element did not work because it is parsed as literal). [#24930](https://github.com/ClickHouse/ClickHouse/pull/24930) ([Amos Bird](https://github.com/amosbird)).
* Improved log messages of S3 errors, no more double whitespaces in case of empty keys and buckets. [#24897](https://github.com/ClickHouse/ClickHouse/pull/24897) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Some queries require multi-pass semantic analysis. Try reusing built sets for `IN` in this case. [#24874](https://github.com/ClickHouse/ClickHouse/pull/24874) ([Amos Bird](https://github.com/amosbird)).
* Respect `max_distributed_connections` for `insert_distributed_sync` (otherwise for huge clusters and sync insert it may run out of `max_thread_pool_size`). [#24754](https://github.com/ClickHouse/ClickHouse/pull/24754) ([Azat Khuzhin](https://github.com/azat)).
* Avoid hiding errors like `Limit for rows or bytes to read exceeded` for scalar subqueries. [#24545](https://github.com/ClickHouse/ClickHouse/pull/24545) ([nvartolomei](https://github.com/nvartolomei)).
* Make String-to-Int parser stricter so that `toInt64('+')` will throw. [#24475](https://github.com/ClickHouse/ClickHouse/pull/24475) ([Amos Bird](https://github.com/amosbird)).
* If `SSD_CACHE` is created with DDL query, it can be created only inside `user_files` directory. [#24466](https://github.com/ClickHouse/ClickHouse/pull/24466) ([Maksim Kita](https://github.com/kitaisreal)).
* PostgreSQL support for specifying non default schema for insert queries. Closes [#24149](https://github.com/ClickHouse/ClickHouse/issues/24149). [#24413](https://github.com/ClickHouse/ClickHouse/pull/24413) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix IPv6 addresses resolving (i.e. fixes `select * from remote('[::1]', system.one)`). [#24319](https://github.com/ClickHouse/ClickHouse/pull/24319) ([Azat Khuzhin](https://github.com/azat)).
* Fix trailing whitespaces in FROM clause with subqueries in multiline mode, and also changes the output of the queries slightly in a more human friendly way. [#24151](https://github.com/ClickHouse/ClickHouse/pull/24151) ([Azat Khuzhin](https://github.com/azat)).
* Improvement for Distributed tables. Add ability to split distributed batch on failures (i.e. due to memory limits, corruptions), under `distributed_directory_monitor_split_batch_on_failure` (OFF by default). [#23864](https://github.com/ClickHouse/ClickHouse/pull/23864) ([Azat Khuzhin](https://github.com/azat)).
* Handle column name clashes for `Join` table engine. Closes [#20309](https://github.com/ClickHouse/ClickHouse/issues/20309). [#23769](https://github.com/ClickHouse/ClickHouse/pull/23769) ([Vladimir](https://github.com/vdimir)).
* Display progress for `File` table engine in `clickhouse-local` and on INSERT query in `clickhouse-client` when data is passed to stdin. Closes [#18209](https://github.com/ClickHouse/ClickHouse/issues/18209). [#23656](https://github.com/ClickHouse/ClickHouse/pull/23656) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Bugfixes and improvements of `clickhouse-copier`. Allow to copy tables with different (but compatible schemas). Closes [#9159](https://github.com/ClickHouse/ClickHouse/issues/9159). Added test to copy ReplacingMergeTree. Closes [#22711](https://github.com/ClickHouse/ClickHouse/issues/22711). Support TTL on columns and Data Skipping Indices. It simply removes it to create internal Distributed table (underlying table will have TTL and skipping indices). Closes [#19384](https://github.com/ClickHouse/ClickHouse/issues/19384). Allow to copy MATERIALIZED and ALIAS columns. There are some cases in which it could be helpful (e.g. if this column is in PRIMARY KEY). Now it could be allowed by setting `allow_to_copy_alias_and_materialized_columns` property to true in task configuration. Closes [#9177](https://github.com/ClickHouse/ClickHouse/issues/9177). Closes [#11007] (https://github.com/ClickHouse/ClickHouse/issues/11007). Closes [#9514](https://github.com/ClickHouse/ClickHouse/issues/9514). Added a property `allow_to_drop_target_partitions` in task configuration to drop partition in original table before moving helping tables. Closes [#20957](https://github.com/ClickHouse/ClickHouse/issues/20957). Get rid of `OPTIMIZE DEDUPLICATE` query. This hack was needed, because `ALTER TABLE MOVE PARTITION` was retried many times and plain MergeTree tables don't have deduplication. Closes [#17966](https://github.com/ClickHouse/ClickHouse/issues/17966). Write progress to ZooKeeper node on path `task_path + /status` in JSON format. Closes [#20955](https://github.com/ClickHouse/ClickHouse/issues/20955). Support for ReplicatedTables without arguments. Closes [#24834](https://github.com/ClickHouse/ClickHouse/issues/24834) .[#23518](https://github.com/ClickHouse/ClickHouse/pull/23518) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Added sleep with backoff between read retries from S3. [#23461](https://github.com/ClickHouse/ClickHouse/pull/23461) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Respect `insert_allow_materialized_columns` (allows materialized columns) for INSERT into `Distributed` table. [#23349](https://github.com/ClickHouse/ClickHouse/pull/23349) ([Azat Khuzhin](https://github.com/azat)).
* Add ability to push down LIMIT for distributed queries. [#23027](https://github.com/ClickHouse/ClickHouse/pull/23027) ([Azat Khuzhin](https://github.com/azat)).
* Fix zero-copy replication with several S3 volumes (Fixes [#22679](https://github.com/ClickHouse/ClickHouse/issues/22679)). [#22864](https://github.com/ClickHouse/ClickHouse/pull/22864) ([ianton-ru](https://github.com/ianton-ru)).
* Resolve the actual port number bound when a user requests any available port from the operating system to show it in the log message. [#25569](https://github.com/ClickHouse/ClickHouse/pull/25569) ([bnaecker](https://github.com/bnaecker)).
* Fixed case, when sometimes conversion of postgres arrays resulted in String data type, not n-dimensional array, because `attndims` works incorrectly in some cases. Closes [#24804](https://github.com/ClickHouse/ClickHouse/issues/24804). [#25538](https://github.com/ClickHouse/ClickHouse/pull/25538) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix convertion of DateTime with timezone for MySQL, PostgreSQL, ODBC. Closes [#5057](https://github.com/ClickHouse/ClickHouse/issues/5057). [#25528](https://github.com/ClickHouse/ClickHouse/pull/25528) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Distinguish KILL MUTATION for different tables (fixes unexpected `Cancelled mutating parts` error). [#25025](https://github.com/ClickHouse/ClickHouse/pull/25025) ([Azat Khuzhin](https://github.com/azat)).
* Allow to declare S3 disk at root of bucket (S3 virtual filesystem is an experimental feature under development). [#24898](https://github.com/ClickHouse/ClickHouse/pull/24898) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Enable reading of subcolumns (e.g. components of Tuples) for distributed tables. [#24472](https://github.com/ClickHouse/ClickHouse/pull/24472) ([Anton Popov](https://github.com/CurtizJ)).
* A feature for MySQL compatibility protocol: make `user` function to return correct output. Closes [#25697](https://github.com/ClickHouse/ClickHouse/pull/25697). [#25697](https://github.com/ClickHouse/ClickHouse/pull/25697) ([sundyli](https://github.com/sundy-li)).
#### Bug Fix
* Improvement for backward compatibility. Use old modulo function version when used in partition key. Closes [#23508](https://github.com/ClickHouse/ClickHouse/issues/23508). [#24157](https://github.com/ClickHouse/ClickHouse/pull/24157) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix extremely rare bug on low-memory servers which can lead to the inability to perform merges without restart. Possibly fixes [#24603](https://github.com/ClickHouse/ClickHouse/issues/24603). [#24872](https://github.com/ClickHouse/ClickHouse/pull/24872) ([alesapin](https://github.com/alesapin)).
* Fix extremely rare error `Tagging already tagged part` in replication queue during concurrent `alter move/replace partition`. Possibly fixes [#22142](https://github.com/ClickHouse/ClickHouse/issues/22142). [#24961](https://github.com/ClickHouse/ClickHouse/pull/24961) ([alesapin](https://github.com/alesapin)).
* Fix potential crash when calculating aggregate function states by aggregation of aggregate function states of other aggregate functions (not a practical use case). See [#24523](https://github.com/ClickHouse/ClickHouse/issues/24523). [#25015](https://github.com/ClickHouse/ClickHouse/pull/25015) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the behavior when query `SYSTEM RESTART REPLICA` or `SYSTEM SYNC REPLICA` does not finish. This was detected on server with extremely low amount of RAM. [#24457](https://github.com/ClickHouse/ClickHouse/pull/24457) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix bug which can lead to ZooKeeper client hung inside clickhouse-server. [#24721](https://github.com/ClickHouse/ClickHouse/pull/24721) ([alesapin](https://github.com/alesapin)).
* If ZooKeeper connection was lost and replica was cloned after restoring the connection, its replication queue might contain outdated entries. Fixed failed assertion when replication queue contains intersecting virtual parts. It may rarely happen if some data part was lost. Print error in log instead of terminating. [#24777](https://github.com/ClickHouse/ClickHouse/pull/24777) ([tavplubix](https://github.com/tavplubix)).
* Fix lost `WHERE` condition in expression-push-down optimization of query plan (setting `query_plan_filter_push_down = 1` by default). Fixes [#25368](https://github.com/ClickHouse/ClickHouse/issues/25368). [#25370](https://github.com/ClickHouse/ClickHouse/pull/25370) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix bug which can lead to intersecting parts after merges with TTL: `Part all_40_40_0 is covered by all_40_40_1 but should be merged into all_40_41_1. This shouldn't happen often.`. [#25549](https://github.com/ClickHouse/ClickHouse/pull/25549) ([alesapin](https://github.com/alesapin)).
* On ZooKeeper connection loss `ReplicatedMergeTree` table might wait for background operations to complete before trying to reconnect. It's fixed, now background operations are stopped forcefully. [#25306](https://github.com/ClickHouse/ClickHouse/pull/25306) ([tavplubix](https://github.com/tavplubix)).
* Fix error `Key expression contains comparison between inconvertible types` for queries with `ARRAY JOIN` in case if array is used in primary key. Fixes [#8247](https://github.com/ClickHouse/ClickHouse/issues/8247). [#25546](https://github.com/ClickHouse/ClickHouse/pull/25546) ([Anton Popov](https://github.com/CurtizJ)).
* Fix wrong totals for query `WITH TOTALS` and `WITH FILL`. Fixes [#20872](https://github.com/ClickHouse/ClickHouse/issues/20872). [#25539](https://github.com/ClickHouse/ClickHouse/pull/25539) ([Anton Popov](https://github.com/CurtizJ)).
* Fix data race when querying `system.clusters` while reloading the cluster configuration at the same time. [#25737](https://github.com/ClickHouse/ClickHouse/pull/25737) ([Amos Bird](https://github.com/amosbird)).
* Fixed `No such file or directory` error on moving `Distributed` table between databases. Fixes [#24971](https://github.com/ClickHouse/ClickHouse/issues/24971). [#25667](https://github.com/ClickHouse/ClickHouse/pull/25667) ([tavplubix](https://github.com/tavplubix)).
* `REPLACE PARTITION` might be ignored in rare cases if the source partition was empty. It's fixed. Fixes [#24869](https://github.com/ClickHouse/ClickHouse/issues/24869). [#25665](https://github.com/ClickHouse/ClickHouse/pull/25665) ([tavplubix](https://github.com/tavplubix)).
* Fixed a bug in `Replicated` database engine that might rarely cause some replica to skip enqueued DDL query. [#24805](https://github.com/ClickHouse/ClickHouse/pull/24805) ([tavplubix](https://github.com/tavplubix)).
* Fix null pointer dereference in `EXPLAIN AST` without query. [#25631](https://github.com/ClickHouse/ClickHouse/pull/25631) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix waiting of automatic dropping of empty parts. It could lead to full filling of background pool and stuck of replication. [#23315](https://github.com/ClickHouse/ClickHouse/pull/23315) ([Anton Popov](https://github.com/CurtizJ)).
* Fix restore of a table stored in S3 virtual filesystem (it is an experimental feature not ready for production). [#25601](https://github.com/ClickHouse/ClickHouse/pull/25601) ([ianton-ru](https://github.com/ianton-ru)).
* Fix nullptr dereference in `Arrow` format when using `Decimal256`. Add `Decimal256` support for `Arrow` format. [#25531](https://github.com/ClickHouse/ClickHouse/pull/25531) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix excessive underscore before the names of the preprocessed configuration files. [#25431](https://github.com/ClickHouse/ClickHouse/pull/25431) ([Vitaly Baranov](https://github.com/vitlibar)).
* A fix for `clickhouse-copier` tool: Fix segfault when sharding_key is absent in task config for copier. [#25419](https://github.com/ClickHouse/ClickHouse/pull/25419) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix `REPLACE` column transformer when used in DDL by correctly quoting the formated query. This fixes [#23925](https://github.com/ClickHouse/ClickHouse/issues/23925). [#25391](https://github.com/ClickHouse/ClickHouse/pull/25391) ([Amos Bird](https://github.com/amosbird)).
* Fix the possibility of non-deterministic behaviour of the `quantileDeterministic` function and similar. This closes [#20480](https://github.com/ClickHouse/ClickHouse/issues/20480). [#25313](https://github.com/ClickHouse/ClickHouse/pull/25313) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support `SimpleAggregateFunction(LowCardinality)` for `SummingMergeTree`. Fixes [#25134](https://github.com/ClickHouse/ClickHouse/issues/25134). [#25300](https://github.com/ClickHouse/ClickHouse/pull/25300) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix logical error with exception message "Cannot sum Array/Tuple in min/maxMap". [#25298](https://github.com/ClickHouse/ClickHouse/pull/25298) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix error `Bad cast from type DB::ColumnLowCardinality to DB::ColumnVector<char8_t>` for queries where `LowCardinality` argument was used for IN (this bug appeared in 21.6). Fixes [#25187](https://github.com/ClickHouse/ClickHouse/issues/25187). [#25290](https://github.com/ClickHouse/ClickHouse/pull/25290) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix incorrect behaviour of `joinGetOrNull` with not-nullable columns. This fixes [#24261](https://github.com/ClickHouse/ClickHouse/issues/24261). [#25288](https://github.com/ClickHouse/ClickHouse/pull/25288) ([Amos Bird](https://github.com/amosbird)).
* Fix incorrect behaviour and UBSan report in big integers. In previous versions `CAST(1e19 AS UInt128)` returned zero. [#25279](https://github.com/ClickHouse/ClickHouse/pull/25279) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed an error which occurred while inserting a subset of columns using CSVWithNames format. Fixes [#25129](https://github.com/ClickHouse/ClickHouse/issues/25129). [#25169](https://github.com/ClickHouse/ClickHouse/pull/25169) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Do not use table's projection for `SELECT` with `FINAL`. It is not supported yet. [#25163](https://github.com/ClickHouse/ClickHouse/pull/25163) ([Amos Bird](https://github.com/amosbird)).
* Fix possible parts loss after updating up to 21.5 in case table used `UUID` in partition key. (It is not recommended to use `UUID` in partition key). Fixes [#25070](https://github.com/ClickHouse/ClickHouse/issues/25070). [#25127](https://github.com/ClickHouse/ClickHouse/pull/25127) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix crash in query with cross join and `joined_subquery_requires_alias = 0`. Fixes [#24011](https://github.com/ClickHouse/ClickHouse/issues/24011). [#25082](https://github.com/ClickHouse/ClickHouse/pull/25082) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix bug with constant maps in mapContains function that lead to error `empty column was returned by function mapContains`. Closes [#25077](https://github.com/ClickHouse/ClickHouse/issues/25077). [#25080](https://github.com/ClickHouse/ClickHouse/pull/25080) ([Kruglov Pavel](https://github.com/Avogar)).
* Remove possibility to create tables with columns referencing themselves like `a UInt32 ALIAS a + 1` or `b UInt32 MATERIALIZED b`. Fixes [#24910](https://github.com/ClickHouse/ClickHouse/issues/24910), [#24292](https://github.com/ClickHouse/ClickHouse/issues/24292). [#25059](https://github.com/ClickHouse/ClickHouse/pull/25059) ([alesapin](https://github.com/alesapin)).
* Fix wrong result when using aggregate projection with *not empty* `GROUP BY` key to execute query with `GROUP BY` by *empty* key. [#25055](https://github.com/ClickHouse/ClickHouse/pull/25055) ([Amos Bird](https://github.com/amosbird)).
* Fix serialization of splitted nested messages in Protobuf format. This PR fixes [#24647](https://github.com/ClickHouse/ClickHouse/issues/24647). [#25000](https://github.com/ClickHouse/ClickHouse/pull/25000) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix limit/offset settings for distributed queries (ignore on the remote nodes). [#24940](https://github.com/ClickHouse/ClickHouse/pull/24940) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible heap-buffer-overflow in `Arrow` format. [#24922](https://github.com/ClickHouse/ClickHouse/pull/24922) ([Kruglov Pavel](https://github.com/Avogar)).
* Fixed possible error 'Cannot read from istream at offset 0' when reading a file from DiskS3 (S3 virtual filesystem is an experimental feature under development that should not be used in production). [#24885](https://github.com/ClickHouse/ClickHouse/pull/24885) ([Pavel Kovalenko](https://github.com/Jokser)).
* Fix "Missing columns" exception when joining Distributed Materialized View. [#24870](https://github.com/ClickHouse/ClickHouse/pull/24870) ([Azat Khuzhin](https://github.com/azat)).
* Allow `NULL` values in postgresql compatibility protocol. Closes [#22622](https://github.com/ClickHouse/ClickHouse/issues/22622). [#24857](https://github.com/ClickHouse/ClickHouse/pull/24857) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix bug when exception `Mutation was killed` can be thrown to the client on mutation wait when mutation not loaded into memory yet. [#24809](https://github.com/ClickHouse/ClickHouse/pull/24809) ([alesapin](https://github.com/alesapin)).
* Fixed bug in deserialization of random generator state with might cause some data types such as `AggregateFunction(groupArraySample(N), T))` to behave in a non-deterministic way. [#24538](https://github.com/ClickHouse/ClickHouse/pull/24538) ([tavplubix](https://github.com/tavplubix)).
* Disallow building uniqXXXXStates of other aggregation states. [#24523](https://github.com/ClickHouse/ClickHouse/pull/24523) ([Raúl Marín](https://github.com/Algunenano)). Then allow it back by actually eliminating the root cause of the related issue. ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix usage of tuples in `CREATE .. AS SELECT` queries. [#24464](https://github.com/ClickHouse/ClickHouse/pull/24464) ([Anton Popov](https://github.com/CurtizJ)).
* Fix computation of total bytes in `Buffer` table. In current ClickHouse version total_writes.bytes counter decreases too much during the buffer flush. It leads to counter overflow and totalBytes return something around 17.44 EB some time after the flush. [#24450](https://github.com/ClickHouse/ClickHouse/pull/24450) ([DimasKovas](https://github.com/DimasKovas)).
* Fix incorrect information about the monotonicity of toWeek function. This fixes [#24422](https://github.com/ClickHouse/ClickHouse/issues/24422) . This bug was introduced in https://github.com/ClickHouse/ClickHouse/pull/5212 , and was exposed later by smarter partition pruner. [#24446](https://github.com/ClickHouse/ClickHouse/pull/24446) ([Amos Bird](https://github.com/amosbird)).
* When user authentication is managed by LDAP. Fixed potential deadlock that can happen during LDAP role (re)mapping, when LDAP group is mapped to a nonexistent local role. [#24431](https://github.com/ClickHouse/ClickHouse/pull/24431) ([Denis Glazachev](https://github.com/traceon)).
* In "multipart/form-data" message consider the CRLF preceding a boundary as part of it. Fixes [#23905](https://github.com/ClickHouse/ClickHouse/issues/23905). [#24399](https://github.com/ClickHouse/ClickHouse/pull/24399) ([Ivan](https://github.com/abyss7)).
* Fix drop partition with intersect fake parts. In rare cases there might be parts with mutation version greater than current block number. [#24321](https://github.com/ClickHouse/ClickHouse/pull/24321) ([Amos Bird](https://github.com/amosbird)).
* Fixed a bug in moving Materialized View from Ordinary to Atomic database (`RENAME TABLE` query). Now inner table is moved to new database together with Materialized View. Fixes [#23926](https://github.com/ClickHouse/ClickHouse/issues/23926). [#24309](https://github.com/ClickHouse/ClickHouse/pull/24309) ([tavplubix](https://github.com/tavplubix)).
* Allow empty HTTP headers. Fixes [#23901](https://github.com/ClickHouse/ClickHouse/issues/23901). [#24285](https://github.com/ClickHouse/ClickHouse/pull/24285) ([Ivan](https://github.com/abyss7)).
* Correct processing of mutations (ALTER UPDATE/DELETE) in Memory tables. Closes [#24274](https://github.com/ClickHouse/ClickHouse/issues/24274). [#24275](https://github.com/ClickHouse/ClickHouse/pull/24275) ([flynn](https://github.com/ucasfl)).
* Make column LowCardinality property in JOIN output the same as in the input, close [#23351](https://github.com/ClickHouse/ClickHouse/issues/23351), close [#20315](https://github.com/ClickHouse/ClickHouse/issues/20315). [#24061](https://github.com/ClickHouse/ClickHouse/pull/24061) ([Vladimir](https://github.com/vdimir)).
* A fix for Kafka tables. Fix the bug in failover behavior when Engine = Kafka was not able to start consumption if the same consumer had an empty assignment previously. Closes [#21118](https://github.com/ClickHouse/ClickHouse/issues/21118). [#21267](https://github.com/ClickHouse/ClickHouse/pull/21267) ([filimonov](https://github.com/filimonov)).
#### Build/Testing/Packaging Improvement
* Add `darwin-aarch64` (Mac M1 / Apple Silicon) builds in CI [#25560](https://github.com/ClickHouse/ClickHouse/pull/25560) ([Ivan](https://github.com/abyss7)) and put the links to the docs and website ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Adds cross-platform embedding of binary resources into executables. It works on Illumos. [#25146](https://github.com/ClickHouse/ClickHouse/pull/25146) ([bnaecker](https://github.com/bnaecker)).
* Add join related options to stress tests to improve fuzzing. [#25200](https://github.com/ClickHouse/ClickHouse/pull/25200) ([Vladimir](https://github.com/vdimir)).
* Enable build with s3 module in osx [#25217](https://github.com/ClickHouse/ClickHouse/issues/25217). [#25218](https://github.com/ClickHouse/ClickHouse/pull/25218) ([kevin wan](https://github.com/MaxWk)).
* Add integration test cases to cover JDBC bridge. [#25047](https://github.com/ClickHouse/ClickHouse/pull/25047) ([Zhichun Wu](https://github.com/zhicwu)).
* Integration tests configuration has special treatment for dictionaries. Removed remaining dictionaries manual setup. [#24728](https://github.com/ClickHouse/ClickHouse/pull/24728) ([Ilya Yatsishin](https://github.com/qoega)).
* Add libfuzzer tests for YAMLParser class. [#24480](https://github.com/ClickHouse/ClickHouse/pull/24480) ([BoloniniD](https://github.com/BoloniniD)).
* Ubuntu 20.04 is now used to run integration tests, docker-compose version used to run integration tests is updated to 1.28.2. Environment variables now take effect on docker-compose. Rework test_dictionaries_all_layouts_separate_sources to allow parallel run. [#20393](https://github.com/ClickHouse/ClickHouse/pull/20393) ([Ilya Yatsishin](https://github.com/qoega)).
* Fix TOCTOU error in installation script. [#25277](https://github.com/ClickHouse/ClickHouse/pull/25277) ([alexey-milovidov](https://github.com/alexey-milovidov)).
### ClickHouse release 21.6, 2021-06-05
#### Upgrade Notes
* `zstd` compression library is updated to v1.5.0. You may get messages about "checksum does not match" in replication. These messages are expected due to update of compression algorithm and you can ignore them. These messages are informational and do not indicate any kinds of undesired behaviour.
* The setting `compile_expressions` is enabled by default. Although it has been heavily tested on variety of scenarios, if you find some undesired behaviour on your servers, you can try turning this setting off.
* Values of `UUID` type cannot be compared with integer. For example, instead of writing `uuid != 0` type `uuid != '00000000-0000-0000-0000-000000000000'`.
#### New Feature
* Add Postgres-like cast operator (`::`). E.g.: `[1, 2]::Array(UInt8)`, `0.1::Decimal(4, 4)`, `number::UInt16`. [#23871](https://github.com/ClickHouse/ClickHouse/pull/23871) ([Anton Popov](https://github.com/CurtizJ)).
* Make big integers production ready. Add support for `UInt128` data type. Fix known issues with the `Decimal256` data type. Support big integers in dictionaries. Support `gcd`/`lcm` functions for big integers. Support big integers in array search and conditional functions. Support `LowCardinality(UUID)`. Support big integers in `generateRandom` table function and `clickhouse-obfuscator`. Fix error with returning `UUID` from scalar subqueries. This fixes [#7834](https://github.com/ClickHouse/ClickHouse/issues/7834). This fixes [#23936](https://github.com/ClickHouse/ClickHouse/issues/23936). This fixes [#4176](https://github.com/ClickHouse/ClickHouse/issues/4176). This fixes [#24018](https://github.com/ClickHouse/ClickHouse/issues/24018). Backward incompatible change: values of `UUID` type cannot be compared with integer. For example, instead of writing `uuid != 0` type `uuid != '00000000-0000-0000-0000-000000000000'`. [#23631](https://github.com/ClickHouse/ClickHouse/pull/23631) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Support `Array` data type for inserting and selecting data in `Arrow`, `Parquet` and `ORC` formats. [#21770](https://github.com/ClickHouse/ClickHouse/pull/21770) ([taylor12805](https://github.com/taylor12805)).
* Implement table comments. Closes [#23225](https://github.com/ClickHouse/ClickHouse/issues/23225). [#23548](https://github.com/ClickHouse/ClickHouse/pull/23548) ([flynn](https://github.com/ucasFL)).
* Support creating dictionaries with DDL queries in `clickhouse-local`. Closes [#22354](https://github.com/ClickHouse/ClickHouse/issues/22354). Added support for `DETACH DICTIONARY PERMANENTLY`. Added support for `EXCHANGE DICTIONARIES` for `Atomic` database engine. Added support for moving dictionaries between databases using `RENAME DICTIONARY`. [#23436](https://github.com/ClickHouse/ClickHouse/pull/23436) ([Maksim Kita](https://github.com/kitaisreal)).
* Add aggregate function `uniqTheta` to support [Theta Sketch](https://datasketches.apache.org/docs/Theta/ThetaSketchFramework.html) in ClickHouse. [#23894](https://github.com/ClickHouse/ClickHouse/pull/23894). [#22609](https://github.com/ClickHouse/ClickHouse/pull/22609) ([Ping Yu](https://github.com/pingyu)).
* Add function `splitByRegexp`. [#24077](https://github.com/ClickHouse/ClickHouse/pull/24077) ([abel-cheng](https://github.com/abel-cheng)).
* Add function `arrayProduct` which accept an array as the parameter, and return the product of all the elements in array. Closes [#21613](https://github.com/ClickHouse/ClickHouse/issues/21613). [#23782](https://github.com/ClickHouse/ClickHouse/pull/23782) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `thread_name` column in `system.stack_trace`. This closes [#23256](https://github.com/ClickHouse/ClickHouse/issues/23256). [#24124](https://github.com/ClickHouse/ClickHouse/pull/24124) ([abel-cheng](https://github.com/abel-cheng)).
* If `insert_null_as_default` = 1, insert default values instead of NULL in `INSERT ... SELECT` and `INSERT ... SELECT ... UNION ALL ...` queries. Closes [#22832](https://github.com/ClickHouse/ClickHouse/issues/22832). [#23524](https://github.com/ClickHouse/ClickHouse/pull/23524) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add support for progress indication in `clickhouse-local` with `--progress` option. [#23196](https://github.com/ClickHouse/ClickHouse/pull/23196) ([Egor Savin](https://github.com/Amesaru)).
* Add support for HTTP compression (determined by `Content-Encoding` HTTP header) in `http` dictionary source. This fixes [#8912](https://github.com/ClickHouse/ClickHouse/issues/8912). [#23946](https://github.com/ClickHouse/ClickHouse/pull/23946) ([FArthur-cmd](https://github.com/FArthur-cmd)).
* Added `SYSTEM QUERY RELOAD MODEL`, `SYSTEM QUERY RELOAD MODELS`. Closes [#18722](https://github.com/ClickHouse/ClickHouse/issues/18722). [#23182](https://github.com/ClickHouse/ClickHouse/pull/23182) ([Maksim Kita](https://github.com/kitaisreal)).
* Add setting `json` (boolean, 0 by default) for `EXPLAIN PLAN` query. When enabled, query output will be a single `JSON` row. It is recommended to use `TSVRaw` format to avoid unnecessary escaping. [#23082](https://github.com/ClickHouse/ClickHouse/pull/23082) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Add setting `indexes` (boolean, disabled by default) to `EXPLAIN PIPELINE` query. When enabled, shows used indexes, number of filtered parts and granules for every index applied. Supported for `MergeTree*` tables. [#22352](https://github.com/ClickHouse/ClickHouse/pull/22352) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* LDAP: implemented user DN detection functionality to use when mapping Active Directory groups to ClickHouse roles. [#22228](https://github.com/ClickHouse/ClickHouse/pull/22228) ([Denis Glazachev](https://github.com/traceon)).
* New aggregate function `deltaSumTimestamp` for summing the difference between consecutive rows while maintaining ordering during merge by storing timestamps. [#21888](https://github.com/ClickHouse/ClickHouse/pull/21888) ([Russ Frank](https://github.com/rf)).
* Added less secure IMDS credentials provider for S3 which works under docker correctly. [#21852](https://github.com/ClickHouse/ClickHouse/pull/21852) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Add back `indexHint` function. This is for [#21238](https://github.com/ClickHouse/ClickHouse/issues/21238). This reverts [#9542](https://github.com/ClickHouse/ClickHouse/pull/9542). This fixes [#9540](https://github.com/ClickHouse/ClickHouse/issues/9540). [#21304](https://github.com/ClickHouse/ClickHouse/pull/21304) ([Amos Bird](https://github.com/amosbird)).
#### Experimental Feature
* Add `PROJECTION` support for `MergeTree*` tables. [#20202](https://github.com/ClickHouse/ClickHouse/pull/20202) ([Amos Bird](https://github.com/amosbird)).
#### Performance Improvement
* Enable `compile_expressions` setting by default. When this setting enabled, compositions of simple functions and operators will be compiled to native code with LLVM at runtime. [#8482](https://github.com/ClickHouse/ClickHouse/pull/8482) ([Maksim Kita](https://github.com/kitaisreal), [alexey-milovidov](https://github.com/alexey-milovidov)). Note: if you feel in trouble, turn this option off.
* Update `re2` library. Performance of regular expressions matching is improved. Also this PR adds compatibility with gcc-11. [#24196](https://github.com/ClickHouse/ClickHouse/pull/24196) ([Raúl Marín](https://github.com/Algunenano)).
* ORC input format reading by stripe instead of reading entire table into memory by once which is cost memory when file size is huge. [#23102](https://github.com/ClickHouse/ClickHouse/pull/23102) ([Chao Ma](https://github.com/godliness)).
* Fusion of aggregate functions `sum`, `count` and `avg` in a query into single aggregate function. The optimization is controlled with the `optimize_fuse_sum_count_avg` setting. This is implemented with a new aggregate function `sumCount`. This function returns a tuple of two fields: `sum` and `count`. [#21337](https://github.com/ClickHouse/ClickHouse/pull/21337) ([hexiaoting](https://github.com/hexiaoting)).
* Update `zstd` to v1.5.0. The performance of compression is improved for single digits percentage. [#24135](https://github.com/ClickHouse/ClickHouse/pull/24135) ([Raúl Marín](https://github.com/Algunenano)). Note: you may get messages about "checksum does not match" in replication. These messages are expected due to update of compression algorithm and you can ignore them.
* Improved performance of `Buffer` tables: do not acquire lock for total_bytes/total_rows for `Buffer` engine. [#24066](https://github.com/ClickHouse/ClickHouse/pull/24066) ([Azat Khuzhin](https://github.com/azat)).
* Preallocate support for hashed/sparse_hashed dictionaries is returned. [#23979](https://github.com/ClickHouse/ClickHouse/pull/23979) ([Azat Khuzhin](https://github.com/azat)).
* Enable `async_socket_for_remote` by default (lower amount of threads in querying Distributed tables with large fanout). [#23683](https://github.com/ClickHouse/ClickHouse/pull/23683) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
#### Improvement
* Add `_partition_value` virtual column to MergeTree table family. It can be used to prune partition in a deterministic way. It's needed to implement partition matcher for mutations. [#23673](https://github.com/ClickHouse/ClickHouse/pull/23673) ([Amos Bird](https://github.com/amosbird)).
* Added `region` parameter for S3 storage and disk. [#23846](https://github.com/ClickHouse/ClickHouse/pull/23846) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Allow configuring different log levels for different logging channels. Closes [#19569](https://github.com/ClickHouse/ClickHouse/issues/19569). [#23857](https://github.com/ClickHouse/ClickHouse/pull/23857) ([filimonov](https://github.com/filimonov)).
* Keep default timezone on `DateTime` operations if it was not provided explicitly. For example, if you add one second to a value of `DateTime` type without timezone it will remain `DateTime` without timezone. In previous versions the value of default timezone was placed to the returned data type explicitly so it becomes DateTime('something'). This closes [#4854](https://github.com/ClickHouse/ClickHouse/issues/4854). [#23392](https://github.com/ClickHouse/ClickHouse/pull/23392) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow user to specify empty string instead of database name for `MySQL` storage. Default database will be used for queries. In previous versions it was working for SELECT queries and not support for INSERT was also added. This closes [#19281](https://github.com/ClickHouse/ClickHouse/issues/19281). This can be useful working with `Sphinx` or other MySQL-compatible foreign databases. [#23319](https://github.com/ClickHouse/ClickHouse/pull/23319) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Function `now64` now supports optional timezone argument. [#24091](https://github.com/ClickHouse/ClickHouse/pull/24091) ([Vasily Nemkov](https://github.com/Enmk)).
* Fix the case when a progress bar in interactive mode in clickhouse-client that appear in the middle of the data may rewrite some parts of visible data in terminal. This closes [#19283](https://github.com/ClickHouse/ClickHouse/issues/19283). [#23050](https://github.com/ClickHouse/ClickHouse/pull/23050) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix crash when memory allocation fails in simdjson. https://github.com/simdjson/simdjson/pull/1567 . Mark as improvement because it's a very rare bug. [#24147](https://github.com/ClickHouse/ClickHouse/pull/24147) ([Amos Bird](https://github.com/amosbird)).
* Preserve dictionaries until storage shutdown (this will avoid possible `external dictionary 'DICT' not found` errors at server shutdown during final flush of the `Buffer` engine). [#24068](https://github.com/ClickHouse/ClickHouse/pull/24068) ([Azat Khuzhin](https://github.com/azat)).
* Flush `Buffer` tables before shutting down tables (within one database), to avoid discarding blocks due to underlying table had been already detached (and `Destination table default.a_data_01870 doesn't exist. Block of data is discarded` error in the log). [#24067](https://github.com/ClickHouse/ClickHouse/pull/24067) ([Azat Khuzhin](https://github.com/azat)).
* Now `prefer_column_name_to_alias = 1` will also favor column names for `group by`, `having` and `order by`. This fixes [#23882](https://github.com/ClickHouse/ClickHouse/issues/23882). [#24022](https://github.com/ClickHouse/ClickHouse/pull/24022) ([Amos Bird](https://github.com/amosbird)).
* Add support for `ORDER BY WITH FILL` with `DateTime64`. [#24016](https://github.com/ClickHouse/ClickHouse/pull/24016) ([kevin wan](https://github.com/MaxWk)).
* Enable `DateTime64` to be a version column in `ReplacingMergeTree`. [#23992](https://github.com/ClickHouse/ClickHouse/pull/23992) ([kevin wan](https://github.com/MaxWk)).
* Log information about OS name, kernel version and CPU architecture on server startup. [#23988](https://github.com/ClickHouse/ClickHouse/pull/23988) ([Azat Khuzhin](https://github.com/azat)).
* Support specifying table schema for `postgresql` dictionary source. Closes [#23958](https://github.com/ClickHouse/ClickHouse/issues/23958). [#23980](https://github.com/ClickHouse/ClickHouse/pull/23980) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add hints for names of `Enum` elements (suggest names in case of typos). Closes [#17112](https://github.com/ClickHouse/ClickHouse/issues/17112). [#23919](https://github.com/ClickHouse/ClickHouse/pull/23919) ([flynn](https://github.com/ucasFL)).
* Measure found rate (the percentage for which the value was found) for dictionaries (see `found_rate` in `system.dictionaries`). [#23916](https://github.com/ClickHouse/ClickHouse/pull/23916) ([Azat Khuzhin](https://github.com/azat)).
* Allow to add specific queue settings via table settng `rabbitmq_queue_settings_list`. (Closes [#23737](https://github.com/ClickHouse/ClickHouse/issues/23737) and [#23918](https://github.com/ClickHouse/ClickHouse/issues/23918)). Allow user to control all RabbitMQ setup: if table setting `rabbitmq_queue_consume` is set to `1` - RabbitMQ table engine will only connect to specified queue and will not perform any RabbitMQ consumer-side setup like declaring exchange, queues, bindings. (Closes [#21757](https://github.com/ClickHouse/ClickHouse/issues/21757)). Add proper cleanup when RabbitMQ table is dropped - delete queues, which the table has declared and all bound exchanges - if they were created by the table. [#23887](https://github.com/ClickHouse/ClickHouse/pull/23887) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add `broken_data_files`/`broken_data_compressed_bytes` into `system.distribution_queue`. Add metric for number of files for asynchronous insertion into Distributed tables that has been marked as broken (`BrokenDistributedFilesToInsert`). [#23885](https://github.com/ClickHouse/ClickHouse/pull/23885) ([Azat Khuzhin](https://github.com/azat)).
* Querying `system.tables` does not go to ZooKeeper anymore. [#23793](https://github.com/ClickHouse/ClickHouse/pull/23793) ([Fuwang Hu](https://github.com/fuwhu)).
* Respect `lock_acquire_timeout_for_background_operations` for `OPTIMIZE` queries. [#23623](https://github.com/ClickHouse/ClickHouse/pull/23623) ([Azat Khuzhin](https://github.com/azat)).
* Possibility to change `S3` disk settings in runtime via new `SYSTEM RESTART DISK` SQL command. [#23429](https://github.com/ClickHouse/ClickHouse/pull/23429) ([Pavel Kovalenko](https://github.com/Jokser)).
* If user applied a misconfiguration by mistakenly setting `max_distributed_connections` to value zero, every query to a `Distributed` table will throw exception with a message containing "logical error". But it's really an expected behaviour, not a logical error, so the exception message was slightly incorrect. It also triggered checks in our CI enviroment that ensures that no logical errors ever happen. Instead we will treat `max_distributed_connections` misconfigured to zero as the minimum possible value (one). [#23348](https://github.com/ClickHouse/ClickHouse/pull/23348) ([Azat Khuzhin](https://github.com/azat)).
* Disable `min_bytes_to_use_mmap_io` by default. [#23322](https://github.com/ClickHouse/ClickHouse/pull/23322) ([Azat Khuzhin](https://github.com/azat)).
* Support `LowCardinality` nullability with `join_use_nulls`, close [#15101](https://github.com/ClickHouse/ClickHouse/issues/15101). [#23237](https://github.com/ClickHouse/ClickHouse/pull/23237) ([vdimir](https://github.com/vdimir)).
* Added possibility to restore `MergeTree` parts to `detached` directory for `S3` disk. [#23112](https://github.com/ClickHouse/ClickHouse/pull/23112) ([Pavel Kovalenko](https://github.com/Jokser)).
* Retries on HTTP connection drops in S3. [#22988](https://github.com/ClickHouse/ClickHouse/pull/22988) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Add settings `external_storage_max_read_rows` and `external_storage_max_read_rows` for MySQL table engine, dictionary source and MaterializeMySQL minor data fetches. [#22697](https://github.com/ClickHouse/ClickHouse/pull/22697) ([TCeason](https://github.com/TCeason)).
* `MaterializeMySQL` (experimental feature): Previously, MySQL 5.7.9 was not supported due to SQL incompatibility. Now leave MySQL parameter verification to the MaterializeMySQL. [#23413](https://github.com/ClickHouse/ClickHouse/pull/23413) ([TCeason](https://github.com/TCeason)).
* Enable reading of subcolumns for distributed tables. [#24472](https://github.com/ClickHouse/ClickHouse/pull/24472) ([Anton Popov](https://github.com/CurtizJ)).
* Fix usage of tuples in `CREATE .. AS SELECT` queries. [#24464](https://github.com/ClickHouse/ClickHouse/pull/24464) ([Anton Popov](https://github.com/CurtizJ)).
* Support for `Parquet` format in `Kafka` tables. [#23412](https://github.com/ClickHouse/ClickHouse/pull/23412) ([Chao Ma](https://github.com/godliness)).
#### Bug Fix
* Use old modulo function version when used in partition key and primary key. Closes [#23508](https://github.com/ClickHouse/ClickHouse/issues/23508). [#24157](https://github.com/ClickHouse/ClickHouse/pull/24157) ([Kseniia Sumarokova](https://github.com/kssenii)). It was a source of backward incompatibility in previous releases.
* Fixed the behavior when query `SYSTEM RESTART REPLICA` or `SYSTEM SYNC REPLICA` is being processed infinitely. This was detected on server with extremely little amount of RAM. [#24457](https://github.com/ClickHouse/ClickHouse/pull/24457) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix incorrect monotonicity of `toWeek` function. This fixes [#24422](https://github.com/ClickHouse/ClickHouse/issues/24422) . This bug was introduced in [#5212](https://github.com/ClickHouse/ClickHouse/pull/5212), and was exposed later by smarter partition pruner. [#24446](https://github.com/ClickHouse/ClickHouse/pull/24446) ([Amos Bird](https://github.com/amosbird)).
* Fix drop partition with intersect fake parts. In rare cases there might be parts with mutation version greater than current block number. [#24321](https://github.com/ClickHouse/ClickHouse/pull/24321) ([Amos Bird](https://github.com/amosbird)).
* Fixed a bug in moving Materialized View from Ordinary to Atomic database (`RENAME TABLE` query). Now inner table is moved to new database together with Materialized View. Fixes [#23926](https://github.com/ClickHouse/ClickHouse/issues/23926). [#24309](https://github.com/ClickHouse/ClickHouse/pull/24309) ([tavplubix](https://github.com/tavplubix)).
* Allow empty HTTP headers in client requests. Fixes [#23901](https://github.com/ClickHouse/ClickHouse/issues/23901). [#24285](https://github.com/ClickHouse/ClickHouse/pull/24285) ([Ivan](https://github.com/abyss7)).
* Set `max_threads = 1` to fix mutation fail of `Memory` tables. Closes [#24274](https://github.com/ClickHouse/ClickHouse/issues/24274). [#24275](https://github.com/ClickHouse/ClickHouse/pull/24275) ([flynn](https://github.com/ucasFL)).
* Fix typo in implementation of `Memory` tables, this bug was introduced at [#15127](https://github.com/ClickHouse/ClickHouse/issues/15127). Closes [#24192](https://github.com/ClickHouse/ClickHouse/issues/24192). [#24193](https://github.com/ClickHouse/ClickHouse/pull/24193) ([张中南](https://github.com/plugine)).
* Fix abnormal server termination due to `HDFS` becoming not accessible during query execution. Closes [#24117](https://github.com/ClickHouse/ClickHouse/issues/24117). [#24191](https://github.com/ClickHouse/ClickHouse/pull/24191) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix crash on updating of `Nested` column with const condition. [#24183](https://github.com/ClickHouse/ClickHouse/pull/24183) ([hexiaoting](https://github.com/hexiaoting)).
* Fix race condition which could happen in RBAC under a heavy load. This PR fixes [#24090](https://github.com/ClickHouse/ClickHouse/issues/24090), [#24134](https://github.com/ClickHouse/ClickHouse/issues/24134),. [#24176](https://github.com/ClickHouse/ClickHouse/pull/24176) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix a rare bug that could lead to a partially initialized table that can serve write requests (insert/alter/so on). Now such tables will be in readonly mode. [#24122](https://github.com/ClickHouse/ClickHouse/pull/24122) ([alesapin](https://github.com/alesapin)).
* Fix an issue: `EXPLAIN PIPELINE` with `SELECT xxx FINAL` showed a wrong pipeline. ([hexiaoting](https://github.com/hexiaoting)).
* Fixed using const `DateTime` value vs `DateTime64` column in `WHERE`. [#24100](https://github.com/ClickHouse/ClickHouse/pull/24100) ([Vasily Nemkov](https://github.com/Enmk)).
* Fix crash in merge JOIN, closes [#24010](https://github.com/ClickHouse/ClickHouse/issues/24010). [#24013](https://github.com/ClickHouse/ClickHouse/pull/24013) ([vdimir](https://github.com/vdimir)).
* Some `ALTER PARTITION` queries might cause `Part A intersects previous part B` and `Unexpected merged part C intersecting drop range D` errors in replication queue. It's fixed. Fixes [#23296](https://github.com/ClickHouse/ClickHouse/issues/23296). [#23997](https://github.com/ClickHouse/ClickHouse/pull/23997) ([tavplubix](https://github.com/tavplubix)).
* Fix SIGSEGV for external GROUP BY and overflow row (i.e. queries like `SELECT FROM GROUP BY WITH TOTALS SETTINGS max_bytes_before_external_group_by>0, max_rows_to_group_by>0, group_by_overflow_mode='any', totals_mode='before_having'`). [#23962](https://github.com/ClickHouse/ClickHouse/pull/23962) ([Azat Khuzhin](https://github.com/azat)).
* Fix keys metrics accounting for `CACHE` dictionary with duplicates in the source (leads to `DictCacheKeysRequestedMiss` overflows). [#23929](https://github.com/ClickHouse/ClickHouse/pull/23929) ([Azat Khuzhin](https://github.com/azat)).
* Fix implementation of connection pool of `PostgreSQL` engine. Closes [#23897](https://github.com/ClickHouse/ClickHouse/issues/23897). [#23909](https://github.com/ClickHouse/ClickHouse/pull/23909) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix `distributed_group_by_no_merge = 2` with `GROUP BY` and aggregate function wrapped into regular function (had been broken in [#23546](https://github.com/ClickHouse/ClickHouse/issues/23546)). Throw exception in case of someone trying to use `distributed_group_by_no_merge = 2` with window functions. Disable `optimize_distributed_group_by_sharding_key` for queries with window functions. [#23906](https://github.com/ClickHouse/ClickHouse/pull/23906) ([Azat Khuzhin](https://github.com/azat)).
* A fix for `s3` table function: better handling of HTTP errors. Response bodies of HTTP errors were being ignored earlier. [#23844](https://github.com/ClickHouse/ClickHouse/pull/23844) ([Vladimir Chebotarev](https://github.com/excitoon)).
* A fix for `s3` table function: better handling of URI's. Fixed an incompatibility with URLs containing `+` symbol, data with such keys could not be read previously. [#23822](https://github.com/ClickHouse/ClickHouse/pull/23822) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Fix error `Can't initialize pipeline with empty pipe` for queries with `GLOBAL IN/JOIN` and `use_hedged_requests`. Fixes [#23431](https://github.com/ClickHouse/ClickHouse/issues/23431). [#23805](https://github.com/ClickHouse/ClickHouse/pull/23805) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix `CLEAR COLUMN` does not work when it is referenced by materialized view. Close [#23764](https://github.com/ClickHouse/ClickHouse/issues/23764). [#23781](https://github.com/ClickHouse/ClickHouse/pull/23781) ([flynn](https://github.com/ucasFL)).
* Fix heap use after free when reading from HDFS if `Values` format is used. [#23761](https://github.com/ClickHouse/ClickHouse/pull/23761) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. [#23744](https://github.com/ClickHouse/ClickHouse/pull/23744) ([Azat Khuzhin](https://github.com/azat)).
* Fixed a bug in recovery of staled `ReplicatedMergeTree` replica. Some metadata updates could be ignored by staled replica if `ALTER` query was executed during downtime of the replica. [#23742](https://github.com/ClickHouse/ClickHouse/pull/23742) ([tavplubix](https://github.com/tavplubix)).
* Fix a bug with `Join` and `WITH TOTALS`, close [#17718](https://github.com/ClickHouse/ClickHouse/issues/17718). [#23549](https://github.com/ClickHouse/ClickHouse/pull/23549) ([vdimir](https://github.com/vdimir)).
* Fix possible `Block structure mismatch` error for queries with `UNION` which could possibly happen after filter-pushdown optimization. Fixes [#23029](https://github.com/ClickHouse/ClickHouse/issues/23029). [#23359](https://github.com/ClickHouse/ClickHouse/pull/23359) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Add type conversion when the setting `optimize_skip_unused_shards_rewrite_in` is enabled. This fixes MSan report. [#23219](https://github.com/ClickHouse/ClickHouse/pull/23219) ([Azat Khuzhin](https://github.com/azat)).
* Add a missing check when updating nested subcolumns, close issue: [#22353](https://github.com/ClickHouse/ClickHouse/issues/22353). [#22503](https://github.com/ClickHouse/ClickHouse/pull/22503) ([hexiaoting](https://github.com/hexiaoting)).
#### Build/Testing/Packaging Improvement
* Support building on Illumos. [#24144](https://github.com/ClickHouse/ClickHouse/pull/24144). Adds support for building on Solaris-derived operating systems. [#23746](https://github.com/ClickHouse/ClickHouse/pull/23746) ([bnaecker](https://github.com/bnaecker)).
* Add more benchmarks for hash tables, including the Swiss Table from Google (that appeared to be slower than ClickHouse hash map in our specific usage scenario). [#24111](https://github.com/ClickHouse/ClickHouse/pull/24111) ([Maksim Kita](https://github.com/kitaisreal)).
* Update librdkafka 1.6.0-RC3 to 1.6.1. [#23874](https://github.com/ClickHouse/ClickHouse/pull/23874) ([filimonov](https://github.com/filimonov)).
* Always enable `asynchronous-unwind-tables` explicitly. It may fix query profiler on AArch64. [#23602](https://github.com/ClickHouse/ClickHouse/pull/23602) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Avoid possible build dependency on locale and filesystem order. This allows reproducible builds. [#23600](https://github.com/ClickHouse/ClickHouse/pull/23600) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Remove a source of nondeterminism from build. Now builds at different point of time will produce byte-identical binaries. Partially addressed [#22113](https://github.com/ClickHouse/ClickHouse/issues/22113). [#23559](https://github.com/ClickHouse/ClickHouse/pull/23559) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add simple tool for benchmarking (Zoo)Keeper. [#23038](https://github.com/ClickHouse/ClickHouse/pull/23038) ([alesapin](https://github.com/alesapin)).
## ClickHouse release 21.5, 2021-05-20
#### Backward Incompatible Change
* Change comparison of integers and floating point numbers when integer is not exactly representable in the floating point data type. In new version comparison will return false as the rounding error will occur. Example: `9223372036854775808.0 != 9223372036854775808`, because the number `9223372036854775808` is not representable as floating point number exactly (and `9223372036854775808.0` is rounded to `9223372036854776000.0`). But in previous version the comparison will return as the numbers are equal, because if the floating point number `9223372036854776000.0` get converted back to UInt64, it will yield `9223372036854775808`. For the reference, the Python programming language also treats these numbers as equal. But this behaviour was dependend on CPU model (different results on AMD64 and AArch64 for some out-of-range numbers), so we make the comparison more precise. It will treat int and float numbers equal only if int is represented in floating point type exactly. [#22595](https://github.com/ClickHouse/ClickHouse/pull/22595) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Remove support for `argMin` and `argMax` for single `Tuple` argument. The code was not memory-safe. The feature was added by mistake and it is confusing for people. These functions can be reintroduced under different names later. This fixes [#22384](https://github.com/ClickHouse/ClickHouse/issues/22384) and reverts [#17359](https://github.com/ClickHouse/ClickHouse/issues/17359). [#23393](https://github.com/ClickHouse/ClickHouse/pull/23393) ([alexey-milovidov](https://github.com/alexey-milovidov)).
#### New Feature
* Added functions `dictGetChildren(dictionary, key)`, `dictGetDescendants(dictionary, key, level)`. Function `dictGetChildren` return all children as an array if indexes. It is a inverse transformation for `dictGetHierarchy`. Function `dictGetDescendants` return all descendants as if `dictGetChildren` was applied `level` times recursively. Zero `level` value is equivalent to infinity. Improved performance of `dictGetHierarchy`, `dictIsIn` functions. Closes [#14656](https://github.com/ClickHouse/ClickHouse/issues/14656). [#22096](https://github.com/ClickHouse/ClickHouse/pull/22096) ([Maksim Kita](https://github.com/kitaisreal)).
* Added function `dictGetOrNull`. It works like `dictGet`, but return `Null` in case key was not found in dictionary. Closes [#22375](https://github.com/ClickHouse/ClickHouse/issues/22375). [#22413](https://github.com/ClickHouse/ClickHouse/pull/22413) ([Maksim Kita](https://github.com/kitaisreal)).
* Added a table function `s3Cluster`, which allows to process files from `s3` in parallel on every node of a specified cluster. [#22012](https://github.com/ClickHouse/ClickHouse/pull/22012) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Added support for replicas and shards in MySQL/PostgreSQL table engine / table function. You can write `SELECT * FROM mysql('host{1,2}-{1|2}', ...)`. Closes [#20969](https://github.com/ClickHouse/ClickHouse/issues/20969). [#22217](https://github.com/ClickHouse/ClickHouse/pull/22217) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added `ALTER TABLE ... FETCH PART ...` query. It's similar to `FETCH PARTITION`, but fetches only one part. [#22706](https://github.com/ClickHouse/ClickHouse/pull/22706) ([turbo jason](https://github.com/songenjie)).
* Added a setting `max_distributed_depth` that limits the depth of recursive queries to `Distributed` tables. Closes [#20229](https://github.com/ClickHouse/ClickHouse/issues/20229). [#21942](https://github.com/ClickHouse/ClickHouse/pull/21942) ([flynn](https://github.com/ucasFL)).
#### Performance Improvement
* Improved performance of `intDiv` by dynamic dispatch for AVX2. This closes [#22314](https://github.com/ClickHouse/ClickHouse/issues/22314). [#23000](https://github.com/ClickHouse/ClickHouse/pull/23000) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improved performance of reading from `ArrowStream` input format for sources other then local file (e.g. URL). [#22673](https://github.com/ClickHouse/ClickHouse/pull/22673) ([nvartolomei](https://github.com/nvartolomei)).
* Disabled compression by default when interacting with localhost (with clickhouse-client or server to server with distributed queries) via native protocol. It may improve performance of some import/export operations. This closes [#22234](https://github.com/ClickHouse/ClickHouse/issues/22234). [#22237](https://github.com/ClickHouse/ClickHouse/pull/22237) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Exclude values that does not belong to the shard from right part of IN section for distributed queries (under `optimize_skip_unused_shards_rewrite_in`, enabled by default, since it still requires `optimize_skip_unused_shards`). [#21511](https://github.com/ClickHouse/ClickHouse/pull/21511) ([Azat Khuzhin](https://github.com/azat)).
* Improved performance of reading a subset of columns with File-like table engine and column-oriented format like Parquet, Arrow or ORC. This closes [#issue:20129](https://github.com/ClickHouse/ClickHouse/issues/20129). [#21302](https://github.com/ClickHouse/ClickHouse/pull/21302) ([keenwolf](https://github.com/keen-wolf)).
* Allow to move more conditions to `PREWHERE` as it was before version 21.1 (adjustment of internal heuristics). Insufficient number of moved condtions could lead to worse performance. [#23397](https://github.com/ClickHouse/ClickHouse/pull/23397) ([Anton Popov](https://github.com/CurtizJ)).
* Improved performance of ODBC connections and fixed all the outstanding issues from the backlog. Using `nanodbc` library instead of `Poco::ODBC`. Closes [#9678](https://github.com/ClickHouse/ClickHouse/issues/9678). Add support for DateTime64 and Decimal* for ODBC table engine. Closes [#21961](https://github.com/ClickHouse/ClickHouse/issues/21961). Fixed issue with cyrillic text being truncated. Closes [#16246](https://github.com/ClickHouse/ClickHouse/issues/16246). Added connection pools for odbc bridge. [#21972](https://github.com/ClickHouse/ClickHouse/pull/21972) ([Kseniia Sumarokova](https://github.com/kssenii)).
#### Improvement
* Increase `max_uri_size` (the maximum size of URL in HTTP interface) to 1 MiB by default. This closes [#21197](https://github.com/ClickHouse/ClickHouse/issues/21197). [#22997](https://github.com/ClickHouse/ClickHouse/pull/22997) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Set `background_fetches_pool_size` to `8` that is better for production usage with frequent small insertions or slow ZooKeeper cluster. [#22945](https://github.com/ClickHouse/ClickHouse/pull/22945) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* FlatDictionary added `initial_array_size`, `max_array_size` options. [#22521](https://github.com/ClickHouse/ClickHouse/pull/22521) ([Maksim Kita](https://github.com/kitaisreal)).
* Add new setting `non_replicated_deduplication_window` for non-replicated MergeTree inserts deduplication. [#22514](https://github.com/ClickHouse/ClickHouse/pull/22514) ([alesapin](https://github.com/alesapin)).
* Update paths to the `CatBoost` model configs in config reloading. [#22434](https://github.com/ClickHouse/ClickHouse/pull/22434) ([Kruglov Pavel](https://github.com/Avogar)).
* Added `Decimal256` type support in dictionaries. `Decimal256` is experimental feature. Closes [#20979](https://github.com/ClickHouse/ClickHouse/issues/20979). [#22960](https://github.com/ClickHouse/ClickHouse/pull/22960) ([Maksim Kita](https://github.com/kitaisreal)).
* Enabled `async_socket_for_remote` by default (using less amount of OS threads for distributed queries). [#23683](https://github.com/ClickHouse/ClickHouse/pull/23683) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).
* Make function name `unhex` case insensitive for compatibility with MySQL. [#23229](https://github.com/ClickHouse/ClickHouse/pull/23229) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Implement functions `arrayHasAny`, `arrayHasAll`, `has`, `indexOf`, `countEqual` for generic case when types of array elements are different. In previous versions the functions `arrayHasAny`, `arrayHasAll` returned false and `has`, `indexOf`, `countEqual` thrown exception. Also add support for `Decimal` and big integer types in functions `has` and similar. This closes [#20272](https://github.com/ClickHouse/ClickHouse/issues/20272). [#23044](https://github.com/ClickHouse/ClickHouse/pull/23044) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Raised the threshold on max number of matches in result of the function `extractAllGroupsHorizontal`. [#23036](https://github.com/ClickHouse/ClickHouse/pull/23036) ([Vasily Nemkov](https://github.com/Enmk)).