release-24.1: sql/stats: evict stats cache entry if user-defined types have changed

[blathers-crl]

Backport 1/3 commits from #124603 and 1/1 commits from #122386 on behalf of @michae2.

/cc @cockroachdb/release

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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.

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multiregionccl: skip TestMRSystemDatabase under stress race

Closes #122363

Release note: None

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Release justification: fix for a serious production issue.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

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  issues or test-only changes.
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[cockroach-teamcity]

This change is 

[michae2]

(Hold off on reviewing while I adjust this.)

[michae2]

Something is going wrong with:

./dev test pkg/ccl/multiregionccl --filter=TestMrSystemDatabase --ignore-cache --race --stress --count 8

I have a feeling we're thrashing the cache when changing the system database to multi-region.

This might be related to #122790 but I'm not sure yet.

[michae2]

Disallowing statistics on system.namespace, system.descriptor, system.comments, and system.zones appears to fix this. I'm trying to understand why. This has something to do with loading descriptors and/or lease acquisition, possibly during ALTER DATABASE system SET PRIMARY REGION.

[michae2]

Disallowing statistics on system.namespace, system.descriptor, system.comments, and system.zones appears to fix this. I'm trying to understand why. This has something to do with loading descriptors and/or lease acquisition, possibly during ALTER DATABASE system SET PRIMARY REGION.

Actually, this seems to be wrong. I think this is simply a flaky test, unrelated to this PR. We skipped it under stressrace on master, so let's do that in 24.1 as well.

[yuzefovich]

I usually ignore Extended CI being red on the backports since it seems to always be red on mine 🤷‍♂️

[michae2]

Ok, this (and all the other backports) are RFAL.