release-22.2: opt: backport fix for ordering-related optimizer panics to v22.2 #113175
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It is possible for some functional-dependency information to be visible to a child operator but invisible to its parent. This could previously cause panics when a child provided an ordering that could be proven to satisfy the required ordering with the child FDs, but not with the parent's FDs. This patch adds a step to the logic that builds provided orderings that ensures a provided ordering can be proven to respect the required ordering without needing additional FD information. This ensures that a parent never needs to know its child's FDs in order to prove that the provided ordering is correct. The extra step is a no-op in the common case when the provided ordering can already be proven to respect the required ordering. Informs cockroachdb#85393 Informs cockroachdb#87806 Fixes cockroachdb#96288 Release note (bug fix): Fixed a rare internal error in the optimizer that has existed since before version 22.1, which could occur while enforcing orderings between SQL operators.
This patch adds a new session setting, `optimizer_use_provided_ordering_fix`, which toggles whether to use the `finalizeProvided` function introduced in required ordering. This setting is on by default, and will be used when backporting cockroachdb#100776. Informs cockroachdb#113072 Release note: None
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This change is |
Yes - there's a default-on setting that can be disabled to disable this change.
If we introduced a bug into the ordering logic, we could cause internal errors and/or incorrect results. This has already baked for months on 23.1 and master, and has an escape hatch, so the risk should be low.
This fixes an incorrect results bug that a customer has hit. |
yuzefovich
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Reviewed 3 of 3 files at r1, 13 of 13 files at r2, all commit messages.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @rafiss)
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Merging since an extraordinary release request has been submitted for this. |
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blathers backport staging-v22.2.16 |
Backport:
Please see individual PRs for details.
/cc @cockroachdb/release
Release justification: Fix for internal error and possible incorrect results in the optimizer.