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release-24.1: sql/stats: fix panic catching in the stats cache, show histogram #136040

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merged 1 commit into from
Nov 26, 2024

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@blathers-crl blathers-crl bot commented Nov 22, 2024

Backport 1/1 commits from #135944 on behalf of @rytaft.

/cc @cockroachdb/release


This commit removes a top-level panic catcher from GetTableStats in the stats
cache, and instead adds a couple of lower level panic catchers. The problems
with the top-level catcher are:

  • There are other entry points into the stats cache besides GetTableStats, so
    it missed some cases.
  • Because the stats cache contains shared state, condition variables, mutexes,
    etc, it was possible to get into a scenario where a panic would bypass
    important logic (such as broadcasting when a resource is available), but the
    panic would be caught at the top level and leave the cache in a bad state.

The new panic catchers are below the level of this shared state manipulation,
but also ensure that all paths into the stats cache that might panic are
covered.

This commit also adds panic catching to SHOW HISTOGRAM so that decoding errors
do not crash the process when running SHOW HISTOGRAM.

Fixes #135940

Release note (bug fix): Fixed an issue where corrupted table statistics could cause the cockroach process to crash.


Release justification:

@blathers-crl blathers-crl bot requested a review from a team as a code owner November 22, 2024 22:20
@blathers-crl blathers-crl bot force-pushed the blathers/backport-release-24.1-135944 branch from 8a626bc to 4846dc8 Compare November 22, 2024 22:20
@blathers-crl blathers-crl bot requested review from rytaft and removed request for a team November 22, 2024 22:20
@blathers-crl blathers-crl bot added blathers-backport This is a backport that Blathers created automatically. O-robot Originated from a bot. labels Nov 22, 2024
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blathers-crl bot commented Nov 22, 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.
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@blathers-crl blathers-crl bot requested a review from michae2 November 22, 2024 22:20
@blathers-crl blathers-crl bot added the backport Label PR's that are backports to older release branches label Nov 22, 2024
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blathers-crl bot commented Nov 22, 2024

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.

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:lgtm:

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: :shipit: complete! 1 of 0 LGTMs obtained (waiting on @rytaft)

@rytaft rytaft requested a review from mgartner November 25, 2024 15:12
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Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: :shipit: complete! 1 of 0 LGTMs obtained (waiting on @blathers-crl[bot] and @rytaft)


pkg/sql/show_histogram.go line 73 at r1 (raw file):

					// manipulate locks.
					if ok, e := errorutil.ShouldCatch(r); ok {
						err = e

See my comment here: #136041 (review)

This commit removes a top-level panic catcher from GetTableStats in the stats
cache, and instead adds a couple of lower level panic catchers. The problems
with the top-level catcher are:
- There are other entry points into the stats cache besides GetTableStats, so
  it missed some cases.
- Because the stats cache contains shared state, condition variables, mutexes,
  etc, it was possible to get into a scenario where a panic would bypass
  important logic (such as broadcasting when a resource is available), but the
  panic would be caught at the top level and leave the cache in a bad state.
The new panic catchers are below the level of this shared state manipulation,
but also ensure that all paths into the stats cache that might panic are
covered.

This commit also adds panic catching to SHOW HISTOGRAM so that decoding errors
do not crash the process when running SHOW HISTOGRAM.

Fixes #135940

Release note (bug fix): Fixed an issue where corrupted table statistics could
cause the cockroach process to crash.
@rytaft rytaft force-pushed the blathers/backport-release-24.1-135944 branch from 4846dc8 to 51a5f2b Compare November 25, 2024 19:49
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Reviewable status: :shipit: complete! 0 of 0 LGTMs obtained (and 1 stale) (waiting on @mgartner and @michae2)


pkg/sql/show_histogram.go line 73 at r1 (raw file):

Previously, mgartner (Marcus Gartner) wrote…

See my comment here: #136041 (review)

Done.

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:lgtm:

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: :shipit: complete! 1 of 0 LGTMs obtained (and 1 stale) (waiting on @blathers-crl[bot])

@rytaft rytaft merged commit b722103 into release-24.1 Nov 26, 2024
18 of 20 checks passed
@rytaft rytaft deleted the blathers/backport-release-24.1-135944 branch November 26, 2024 00:43
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