From a647109aab3afc530e2a6a39b5a0214ea98af2c9 Mon Sep 17 00:00:00 2001 From: Lauren Hirata Singh Date: Mon, 8 May 2023 21:21:28 -0400 Subject: [PATCH 1/5] Additional v23.1 Known Limitations Relates to DOC-7381 --- v23.1/known-limitations.md | 48 +++++++++++++++++++++++++++++++++----- 1 file changed, 42 insertions(+), 6 deletions(-) diff --git a/v23.1/known-limitations.md b/v23.1/known-limitations.md index ca615a4398a..0e7f6011396 100644 --- a/v23.1/known-limitations.md +++ b/v23.1/known-limitations.md @@ -30,17 +30,53 @@ This page describes newly identified limitations in the CockroachDB {{page.relea [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/84680) -### No support for placeholders in `AS OF SYSTEM TIME` +### Limitations for `SELECT FOR UPDATE` -CockroachDB does not support placeholders in [`AS OF SYSTEM TIME`](as-of-system-time.html). This means that the time value has to be embedded in the SQL string. +- [`SELECT FOR UPDATE`](select-for-update.html) places locks on each key scanned by the base index scan. This means that even if some of those keys are later filtered out by a predicate which could not be pushed into the scan, they will still be locked. -[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/30955) + [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/75457) + +- [`SELECT FOR UPDATE`](select-for-update.html) only places an unreplicated lock on the index being scanned by the query. This diverges from PostgreSQL, which aquires a lock on all indexes. + + [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/57031) + +### Limitations for composite types + +- Avro [changefeeds](create-and-configure-changefeeds.html) do not support user-defined composite (tuple) types. + + [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102903) + +- Parquet [changefeeds](create-and-configure-changefeeds.html) do not support user-defined composite (tuple) types. + + [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102904) + +- When CockroachDB serializes a user-defined composite (tuple) type to CSV, the metadata can be inconsistent. + + [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102905) -### `SELECT FOR UPDATE` places locks on each key scanned by the base index scan +### Low estimated RUs are rounded to zero -[`SELECT FOR UPDATE`](select-for-update.html) places locks on each key scanned by the base index scan. This means that even if some of those keys are later filtered out by a predicate which could not be pushed into the scan, they will still be locked. +The RU estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates (i.e., very cheap queries) are rounded down to zero. -[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/75457) +[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/100617) + +### Statistics for deleted tables in `system.table_statistics` do not get removed + +When a table is dropped, the related rows in `system.table_statistics` are not deleted. CockroachDB does not delete old statistics. + +[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/94195) + +### Collect stats for virtual computed columns + +CockroachDB does not collect statistics for [virtual computed columns](computed-columns.html). This can prevent the [optimizer](cost-based-optimizer.html) from accurately calculating the cost of scanning an index on a virtual column, and, transitively, the cost of scanning an [expression index](expression-indexes.html). + +[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/68254) + +### No support for placeholders in `AS OF SYSTEM TIME` + +CockroachDB does not support placeholders in [`AS OF SYSTEM TIME`](as-of-system-time.html). This means that the time value has to be embedded in the SQL string. + +[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/30955) ### Declarative schema changer does not track rows in `system.privileges` From c03ef26b5b53ba4b3e57557e022c25c6c74eceb7 Mon Sep 17 00:00:00 2001 From: Lauren Hirata Singh Date: Tue, 9 May 2023 13:20:19 -0400 Subject: [PATCH 2/5] Add KL92961 --- v23.1/known-limitations.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/v23.1/known-limitations.md b/v23.1/known-limitations.md index 0e7f6011396..3adc988f307 100644 --- a/v23.1/known-limitations.md +++ b/v23.1/known-limitations.md @@ -54,6 +54,12 @@ This page describes newly identified limitations in the CockroachDB {{page.relea [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102905) +### Common table expressions are not supported in user-defined functions + +[Common table expressions](common-table-expressions.html) (CTE), recursive or non-recursive, are not supported in [user-defined functions](user-defined-functions.html) (UDF). That is, you cannot use a `WITH` clause in the body of a UDF. + +[Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/92961) + ### Low estimated RUs are rounded to zero The RU estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates (i.e., very cheap queries) are rounded down to zero. From 4b3296cdd2dc22a7a553d01f8764370de0605893 Mon Sep 17 00:00:00 2001 From: Lauren Hirata Singh Date: Tue, 9 May 2023 17:02:17 -0400 Subject: [PATCH 3/5] Update CDC KL --- v23.1/known-limitations.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/v23.1/known-limitations.md b/v23.1/known-limitations.md index 3adc988f307..88fe8c4c77b 100644 --- a/v23.1/known-limitations.md +++ b/v23.1/known-limitations.md @@ -50,7 +50,7 @@ This page describes newly identified limitations in the CockroachDB {{page.relea [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102904) -- When CockroachDB serializes a user-defined composite (tuple) type to CSV, the metadata can be inconsistent. +- Serializing a user-defined composite (tuple) type to CSV is in [preview](cockroachdb-feature-availability.html): the output format is likely to change in a future minor release, and alterations to the type may not be reflected properly in changefeeds. [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/102905) From 70965ab83cf9379191c12d65c1669ebfb2149802 Mon Sep 17 00:00:00 2001 From: Lauren Hirata Singh Date: Wed, 10 May 2023 15:24:40 -0400 Subject: [PATCH 4/5] Edits based on feedback --- v23.1/known-limitations.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/v23.1/known-limitations.md b/v23.1/known-limitations.md index 88fe8c4c77b..edd32a21fb1 100644 --- a/v23.1/known-limitations.md +++ b/v23.1/known-limitations.md @@ -60,27 +60,27 @@ This page describes newly identified limitations in the CockroachDB {{page.relea [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/92961) -### Low estimated RUs are rounded to zero +### Low estimated Request Units are rounded to zero -The RU estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates (i.e., very cheap queries) are rounded down to zero. +The [Request Units](../cockroachcloud/learn-about-request-units.html) (RUs) estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates (i.e., very cheap queries) are rounded down to zero. [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/100617) ### Statistics for deleted tables in `system.table_statistics` do not get removed -When a table is dropped, the related rows in `system.table_statistics` are not deleted. CockroachDB does not delete old statistics. +When a table is dropped, the related rows in `system.table_statistics` are not deleted. CockroachDB does not delete historical statistics. [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/94195) -### Collect stats for virtual computed columns +### Collection of statistics for virtual computed columns CockroachDB does not collect statistics for [virtual computed columns](computed-columns.html). This can prevent the [optimizer](cost-based-optimizer.html) from accurately calculating the cost of scanning an index on a virtual column, and, transitively, the cost of scanning an [expression index](expression-indexes.html). [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/68254) -### No support for placeholders in `AS OF SYSTEM TIME` +### `AS OF SYSTEM TIME` does not support placeholders -CockroachDB does not support placeholders in [`AS OF SYSTEM TIME`](as-of-system-time.html). This means that the time value has to be embedded in the SQL string. +CockroachDB does not support placeholders in [`AS OF SYSTEM TIME`](as-of-system-time.html). The time value must be embedded in the SQL string. [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/30955) From edee007985248db526347f354fa8e88235c799eb Mon Sep 17 00:00:00 2001 From: Lauren Hirata Singh Date: Mon, 15 May 2023 09:06:39 -0400 Subject: [PATCH 5/5] Minor fix --- v23.1/known-limitations.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/v23.1/known-limitations.md b/v23.1/known-limitations.md index edd32a21fb1..c1aa336b7c3 100644 --- a/v23.1/known-limitations.md +++ b/v23.1/known-limitations.md @@ -62,7 +62,7 @@ This page describes newly identified limitations in the CockroachDB {{page.relea ### Low estimated Request Units are rounded to zero -The [Request Units](../cockroachcloud/learn-about-request-units.html) (RUs) estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates (i.e., very cheap queries) are rounded down to zero. +The [Request Units](../cockroachcloud/learn-about-request-units.html) (RUs) estimate surfaced in [`EXPLAIN ANALYZE`](explain-analyze.html) is displayed as an integer value. Because of this, fractional RU estimates, which represent very inexpensive queries, are rounded down to zero. [Tracking GitHub issue](https://github.com/cockroachdb/cockroach/issues/100617)