Add new known limitations and remove resolved limitations

Fixes #6835.
Fixes #6837.

v19.1/known-limitations.md

@@ -171,14 +171,6 @@ This conversion is currently only well defined for a small range of integers, i.
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/20136)
 
-### Cannot decommission nodes
-
-The [`cockroach node decommission`](https://www.cockroachlabs.com/docs/stable/view-node-details.html#subcommands) command will hang when used to target a set of nodes that cannot be removed without breaking the configured replication rules.
-
-Example: decommissioning a node in a three node cluster will not work because ranges would become under-replicated.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/18029)
-
 ### Importing data using the PostgreSQL COPY protocol
 
 Currently, the built-in SQL shell provided with CockroachDB (`cockroach sql` / `cockroach demo`) does not support importing data using the `COPY` statement. Users can use the `psql` client command provided with PostgreSQL to load this data into CockroachDB instead. For details, see [Import from generic SQL dump](https://www.cockroachlabs.com/docs/stable/import-data.html#import-from-generic-sql-dump).

v19.2/known-limitations.md

@@ -190,14 +190,6 @@ As a workaround, set `default_int_size` via your database driver, or ensure that
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/32846)
 
-### Cannot decommission nodes
-
-The [`cockroach node decommission`](https://www.cockroachlabs.com/docs/stable/cockroach-node.html#subcommands) command will hang when used to target a set of nodes that cannot be removed without breaking the configured replication rules.
-
-Example: decommissioning a node in a three node cluster will not work because ranges would become under-replicated.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/18029)
-
 ### Importing data using the PostgreSQL COPY protocol
 
 Currently, the built-in SQL shell provided with CockroachDB (`cockroach sql` / `cockroach demo`) does not support importing data using the `COPY` statement. Users can use the `psql` client command provided with PostgreSQL to load this data into CockroachDB instead. For details, see [Import from generic SQL dump](https://www.cockroachlabs.com/docs/stable/import-data.html#import-from-generic-sql-dump).

v2.1/known-limitations.md

@@ -134,14 +134,6 @@ This conversion is currently only well defined for a small range of integers, i.
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/20136)
 
-### Cannot decommission nodes
-
-The [`cockroach node decommission`](https://www.cockroachlabs.com/docs/stable/view-node-details.html#subcommands) command will hang when used to target a set of nodes that cannot be removed without breaking the configured replication rules.
-
-Example: decommissioning a node in a three node cluster will not work because ranges would become under-replicated.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/18029)
-
 ### Importing data using the PostgreSQL COPY protocol
 
 Currently, the built-in SQL shell provided with CockroachDB (`cockroach sql` / `cockroach demo`) does not support importing data using the `COPY` statement. Users can use the `psql` client command provided with PostgreSQL to load this data into CockroachDB instead. For details, see [Import from generic SQL dump](https://www.cockroachlabs.com/docs/stable/import-data.html#import-from-generic-sql-dump).

v20.1/known-limitations.md

@@ -6,6 +6,57 @@ toc: true
 
 This page describes newly identified limitations in the CockroachDB {{page.release_info.version}} release as well as unresolved limitations identified in earlier releases.
 
+## New limitations
+
+### `ROLLBACK TO SAVEPOINT` in high-priority transactions containing DDL
+
+Transactions with [priority `HIGH`](transactions.html#transaction-priorities) that contain DDL and `ROLLBACK TO SAVEPOINT` are not supported, as they could result in a deadlock. For example:   
+
+~~~ sql
+> BEGIN PRIORITY HIGH; SAVEPOINT s; CREATE TABLE t(x INT); ROLLBACK TO SAVEPOINT s;
+~~~
+
+~~~
+ERROR: unimplemented: cannot use ROLLBACK TO SAVEPOINT in a HIGH PRIORITY transaction containing DDL
+SQLSTATE: 0A000
+HINT: You have attempted to use a feature that is not yet implemented.
+See: https://github.com/cockroachdb/cockroach/issues/46414
+~~~
+
+[Tracking Github Issue](https://github.com/cockroachdb/cockroach/issues/46414)
+
+### Column name from an outer column inside a subquery differs from PostgreSQL
+
+CockroachDB returns the column name from an outer column inside a subquery as `?column?`, unlike PostgreSQL. For example:
+
+~~~ sql
+> SELECT (SELECT t.*) FROM (VALUES (1)) t(x);
+~~~
+
+CockroachDB:
+
+~~~
+  ?column?
+------------
+         1
+~~~
+
+PostgreSQL:
+
+~~~
+ x
+---
+ 1
+~~~
+
+[Tracking Github Issue](https://github.com/cockroachdb/cockroach/issues/46563)
+
+### Privileges required to access to certain virtual tables differs from PostgreSQL
+
+Access to certain virtual tables in the `pg_catalog` and `information_schema` schemas require more privileges than in PostgreSQL. For example, in CockroachDB, access to `pg_catalog.pg_types` requires the `SELECT` privilege on the current database, whereas this privilege is not required in PostgreSQL.
+
+[Tracking Github Issue](https://github.com/cockroachdb/cockroach/issues/43177)
+
 ## Unresolved limitations
 
 ### Adding stores to a node
@@ -33,7 +84,7 @@ An `x` value less than `1` would result in the following error:
 pq: check constraint violated
 ~~~
 
-[Tracking Github Issue](https://github.com/cockroachdb/cockroach/issues/35370)
+  [Tracking Github Issue](https://github.com/cockroachdb/cockroach/issues/35370)
 
 ### Cold starts of large clusters may require manual intervention
 
@@ -128,56 +179,26 @@ For multi-core systems, the user CPU percent can be greater than 100%. Full util
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/28724)
 
-### `GROUP BY` referring to `SELECT` aliases
-
-Applications developed for PostgreSQL that use `GROUP BY` to refer to column aliases _produced_ in the same `SELECT` clause must be changed to use the full underlying expression instead. For example, `SELECT x+y AS z ... GROUP BY z` must be changed to `SELECT x+y AS z ... GROUP BY x+y`. Otherwise, CockroachDB will produce either a planning error or, in some cases, invalid results.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/28059)
-
 ### `TRUNCATE` does not behave like `DELETE`
 
 `TRUNCATE` is not a DML statement, but instead works as a DDL statement. Its limitations are the same as other DDL statements, which are outlined in [Online Schema Changes: Limitations](online-schema-changes.html#limitations)
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/27953)
 
-### Using columns in `SELECT` not listed in `GROUP BY`
-
-Applications developed for PostgreSQL can exploit the fact that PostgreSQL allows a `SELECT` clause to name a column that is not also listed in `GROUP BY` in some cases, for example `SELECT a GROUP BY b`. This is not yet supported by CockroachDB.
-
-To work around this limitation, and depending on expected results, the rendered columns should be either added at the end of the `GROUP BY` list (e.g., `SELECT a GROUP BY b, a`), or `DISTINCT` should also be used (e.g., `SELECT DISTINCT a GROUP BY b`).
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/26709)
-
-### Cannot `DELETE` multiple rows with self-referencing FKs
-
-Because CockroachDB checks foreign keys eagerly (i.e., per row), it cannot trivially delete multiple rows from a table with a self-referencing foreign key.
-
-To successfully delete multiple rows with self-referencing foreign keys, you need to ensure they're deleted in an order that doesn't violate the foreign key constraint.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/25809)
-
 ### `DISTINCT` operations cannot operate over JSON values
 
 CockroachDB does not currently key-encode JSON values, which prevents `DISTINCT` filters from working on them.
 
 As a workaround, you can return the JSON field's values to a `string` using the `->>` operator, e.g., `SELECT DISTINCT col->>'field'...`.
 
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/24436)
+[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/35706)
 
 ### Current sequence value not checked when updating min/max value
 
 Altering the minimum or maximum value of a series does not check the current value of a series. This means that it is possible to silently set the maximum to a value less than, or a minimum value greater than, the current value.
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/23719)
 
-### Using common table expressions in `VALUES` and `UNION` clauses
-
-When the [cost-based optimizer](cost-based-optimizer.html) is disabled, or when it does not support a query, a common table expression defined outside of a `VALUES` or `UNION `clause will not be available inside it. For example `...WITH a AS (...) SELECT ... FROM (VALUES(SELECT * FROM a))`.
-
-This limitation will be lifted when the cost-based optimizer covers all queries. Until then, applications can work around this limitation by including the entire CTE query in the place where it is used.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/22418)
-
 ### Using `default_int_size` session variable in batch of statements
 
 When setting the `default_int_size` [session variable](set-vars.html) in a batch of statements such as `SET default_int_size='int4'; SELECT 1::IN`, the `default_int_size` variable will not take affect until the next statement. This happens because statement parsing takes place asynchronously from statement execution.
@@ -186,14 +207,6 @@ As a workaround, set `default_int_size` via your database driver, or ensure that
 
 [Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/32846)
 
-### Cannot decommission nodes
-
-The [`cockroach node decommission`](https://www.cockroachlabs.com/docs/stable/cockroach-node.html#subcommands) command will hang when used to target a set of nodes that cannot be removed without breaking the configured replication rules.
-
-Example: decommissioning a node in a three node cluster will not work because ranges would become under-replicated.
-
-[Tracking GitHub Issue](https://github.com/cockroachdb/cockroach/issues/18029)
-
 ### Importing data using the PostgreSQL COPY protocol
 
 Currently, the built-in SQL shell provided with CockroachDB (`cockroach sql` / `cockroach demo`) does not support importing data using the `COPY` statement. Users can use the `psql` client command provided with PostgreSQL to load this data into CockroachDB instead. For details, see [Import from generic SQL dump](https://www.cockroachlabs.com/docs/stable/import-data.html#import-from-generic-sql-dump).