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release-23.1.23-rc: sql/stats: evict stats cache entry if user-defined types have changed #125473

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@blathers-crl blathers-crl bot commented Jun 11, 2024

Backport 1/1 commits from #124603 on behalf of @michae2.

/cc @cockroachdb/release


Backport 1/3 commits from #124603.

/cc @cockroachdb/release


sql/stats: evict stats cache entry if user-defined types have changed

When adding table statistics to the stats cache, we decode histogram upper bounds into datums. If the histogram column uses a user-defined type, we hydrate the type and use this to decode.

In statistics builder, these histogram upper bound datums are compared against datums in spans and constraints. The comparisons assume that the datums are of equivalent type, but if the user-defined type has changed sometime after loading the stats cache entry, this might not be true.

If the user-defined type has changed, we need to evict and re-load the stats cache entry so that we decode histogram datums with a freshly-hydrated type.

(We were already checking UDT versions when building the optTable in sql.(*optCatalog).dataSourceForTable, but the newly-built optTable used the existing table statistics instead of refreshing those, too.)

Fixes: #124181

Release note (bug fix): Fix a bug where a change to a user-defined type could cause queries against tables using that type to fail with an error message like:

histogram.go:694: span must be fully contained in the bucket

The change to the user-defined type could come directly from an ALTER TYPE statement, or indirectly from an ALTER DATABASE ADD REGION or DROP REGION statement (which implicitly change the crdb_internal_region type).

This bug has existed since UDTs were introduced in v20.2.


Release justification: fix for a serious production issue.


Release justification: fix for a serious production issue.

When adding table statistics to the stats cache, we decode histogram
upper bounds into datums. If the histogram column uses a user-defined
type, we hydrate the type and use this to decode.

In statistics builder, these histogram upper bound datums are compared
against datums in spans and constraints. The comparisons assume that the
datums are of equivalent type, but if the user-defined type has changed
sometime after loading the stats cache entry, this might not be true.

If the user-defined type has changed, we need to evict and re-load the
stats cache entry so that we decode histogram datums with a freshly-
hydrated type.

(We were already checking UDT versions when building the optTable in
sql.(*optCatalog).dataSourceForTable, but the newly-built optTable used
the existing table statistics instead of refreshing those, too.)

Fixes: #124181

Release note (bug fix): Fix a bug where a change to a user-defined type
could cause queries against tables using that type to fail with an error
message like:

  "histogram.go:694: span must be fully contained in the bucket"

The change to the user-defined type could come directly from an ALTER
TYPE statement, or indirectly from an ALTER DATABASE ADD REGION or DROP
REGION statement (which implicitly change the crdb_internal_region
type).

This bug has existed since UDTs were introduced in v20.2.
@blathers-crl blathers-crl bot force-pushed the blathers/backport-release-23.1.23-rc-124855 branch from 159c6d5 to 1c8eef6 Compare June 11, 2024 06:17
@blathers-crl blathers-crl bot requested a review from a team as a code owner June 11, 2024 06:17
@blathers-crl blathers-crl bot requested review from yuzefovich and removed request for a team June 11, 2024 06:17
@blathers-crl blathers-crl bot added blathers-backport This is a backport that Blathers created automatically. O-robot Originated from a bot. labels Jun 11, 2024
@blathers-crl blathers-crl bot requested review from mgartner and rafiss June 11, 2024 06:17
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blathers-crl bot commented Jun 11, 2024

Thanks for opening a backport.

Please check the backport criteria before merging:

  • Backports should only be created for serious
    issues
    or test-only changes.
  • Backports should not break backwards-compatibility.
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    here).
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  • There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
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Also, please add a brief release justification to the body of your PR to justify this
backport.

@blathers-crl blathers-crl bot added the backport Label PR's that are backports to older release branches label Jun 11, 2024
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@yuzefovich yuzefovich changed the title release-23.1.23-rc: release-23.1: sql/stats: evict stats cache entry if user-defined types have changed release-23.1.23-rc: sql/stats: evict stats cache entry if user-defined types have changed Jun 11, 2024
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Reviewed 6 of 6 files at r1, all commit messages.
Reviewable status: :shipit: complete! 0 of 0 LGTMs obtained (waiting on @mgartner)

@michae2 michae2 merged commit 8705c1e into release-23.1.23-rc Jun 11, 2024
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@michae2 michae2 deleted the blathers/backport-release-23.1.23-rc-124855 branch June 11, 2024 16:14
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