release-22.1: opt: fix bug with incorrect results produced by paired left lookup join #82076
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Prior to this patch, it was possible for a paired join to produce incorrect results for a left lookup join. In particular, some output rows had non-NULL values for right-side columns when the right-side columns should have been NULL. This commit fixes the issue by updating the optimizer to ensure that only columns from the second join in the paired join (the index join) are projected, not columns from the first (the lookup join). Fixes cockroachdb#81968 Release note (bug fix): Fixed an issue where a left lookup join could have incorrect results. In particular, some output rows could have non-NULL values for right-side columns when the right-side columns should have been NULL. This issue only exists in 22.1.0 and prior development releases of 22.1.
|
Thanks for opening a backport. Please check the backport criteria before merging:
If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.
Add a brief release justification to the body of your PR to justify this backport. Some other things to consider:
|
|
This change is |
msirek
approved these changes
May 30, 2022
There was a problem hiding this comment.
Reviewed 6 of 6 files at r1, all commit messages.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @yuzefovich)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport 1/1 commits from #82054.
/cc @cockroachdb/release
Release justification: fixes a critical correctness issue
Prior to this patch, it was possible for a paired join to produce incorrect
results for a left lookup join. In particular, some output rows had
non-NULL values for right-side columns when the right-side columns should
have been NULL.
This commit fixes the issue by updating the optimizer to ensure that
only columns from the second join in the paired join (the index join)
are projected, not columns from the first (the lookup join).
Fixes #81968
Release note (bug fix): Fixed an issue where a left lookup join could
have incorrect results. In particular, some output rows could have non-NULL
values for right-side columns when the right-side columns should
have been NULL. This issue only exists in 22.1.0 and prior development
releases of 22.1.