opt: fix incorrect results returned by non-recursive WITH RECURSIVE CTE #98042
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Prior to this commit, queries that used a CTE marked as WITH RECURSIVE which did not reference itself (i.e., it was not actually recursive) could return incorrect results. This was because the UNION ALL in the CTE was incorrectly converted to a UNION by the optimizer. This commit fixes the problem by ensuring that UNION ALL is used if the original CTE contained UNION ALL. Fixes cockroachdb#93370 Release note (bug fix): Fixed a bug in which CTEs marked as WITH RECURSIVE which were not actually recursive could return incorrect results. This could happen if the CTE used a UNION ALL, because the optimizer incorrectly converted the UNION ALL to a UNION. This bug has existed since suppport for recursive CTEs was first added in v20.1, and has now been fixed.
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Oopsie.. LGTM |
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TFTRs!
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Encountered an error creating backports. Some common things that can go wrong:
You might need to create your backport manually using the backport tool. error creating merge commit from 74fa893 to blathers/backport-release-22.1-98042: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict [] you may need to manually resolve merge conflicts with the backport tool. Backport to branch 22.1.x failed. See errors above. error creating merge commit from 74fa893 to blathers/backport-release-22.2-98042: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict [] you may need to manually resolve merge conflicts with the backport tool. Backport to branch 22.2.x failed. See errors above. 🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf. |
Prior to this commit, queries that used a CTE marked as
WITH RECURSIVEwhich did not reference itself (i.e., it was not actually recursive) could return incorrect results. This was because theUNION ALLin the CTE was incorrectly converted to aUNIONby the optimizer. This commit fixes the problem by ensuring thatUNION ALLis used if the original CTE containedUNION ALL.Fixes #93370
Release note (bug fix): Fixed a bug in which CTEs marked as
WITH RECURSIVEwhich were not actually recursive could return incorrect results. This could happen if the CTE used aUNION ALL, because the optimizer incorrectly converted theUNION ALLto aUNION. This bug has existed since suppport for recursive CTEs was first added in v20.1, and has now been fixed.