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release-22.1: opt: respect NO_INDEX_JOIN flag

Open blathers-crl[bot] opened this issue 3 years ago • 2 comments

Backport 1/1 commits from #85843 on behalf of @rytaft.

/cc @cockroachdb/release


Prior to this commit, it was possible that the optimizer could produce a plan with an index join even if the user hinted that index joins should be avoided by using the NO_INDEX_JOIN hint. This commit fixes that oversight, and we no longer plan an index join in this case. This commit also adds assertions that an index join is not planned if NO_INDEX_JOIN is used to prevent this bug from recurring.

Fixes #85841

Release note (bug fix): Fixed an issue where the NO_INDEX_JOIN hint could be ignored by the optimizer in some cases, causing it to create a query plan with an index join.


Release justification:

blathers-crl[bot] avatar Aug 10 '22 19:08 blathers-crl[bot]

Thanks for opening a backport.

Please check the backport criteria before merging:

  • [x] Patches should only be created for serious issues or test-only changes.
  • [x] Patches should not break backwards-compatibility.
  • [x] Patches should change as little code as possible.
  • [x] Patches should not change on-disk formats or node communication protocols.
  • [x] Patches should not add new functionality.
  • [x] Patches must not add, edit, or otherwise modify cluster versions; or add version gates.
If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.
  • [ ] There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
  • [ ] The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
  • [ ] New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
  • [ ] The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

  • What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
  • Will this work in a cluster of mixed patch versions? Did we test that?
  • If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

blathers-crl[bot] avatar Aug 10 '22 19:08 blathers-crl[bot]

This change is Reviewable

cockroach-teamcity avatar Aug 10 '22 19:08 cockroach-teamcity