yjhjstz opened a new pull request, #1910: URL: https://github.com/apache/cloudberry/pull/1910
CScalarSortGroupClause inherited COperator::HashValue(), which hashes only the operator id. Since the operator is an arity-0 scalar leaf, the group expression hash equals the operator hash, so every SortGroupClause group expression in the memo landed in one fixed hash bucket (hash(EopScalarSortGroupClause) % GPOPT_MEMO_HT_BUCKETS), determined at compile time. That bucket accumulates all such expressions and acts as a permanent collision target for unrelated arity-0 operators whose hashes happen to be congruent modulo the bucket count. Mix the members that Matches() already compares (tleSortGroupRef, eqop, sortop, nulls_first, hashable) into the hash, matching the convention of other scalar leaves such as CScalarConst and CScalarIdent. Equal operators still hash equally, so the hash/equality contract holds; distinct sort group clauses now spread across buckets, shortening memo hash chains during insertion and CMemo::FRehash. Note this is a hash-quality improvement only: cross-operator bucket collisions remain possible by construction, and type safety relies on the Eopid check in CScalarSortGroupClause::Matches(). Fixes #546 ### What does this PR do? <!-- Brief overview of the changes, including any major features or fixes --> ### Type of Change - [ ] Bug fix (non-breaking change) - [ ] New feature (non-breaking change) - [ ] Breaking change (fix or feature with breaking changes) - [ ] Documentation update ### Breaking Changes <!-- Remove if not applicable. If yes, explain impact and migration path --> ### Test Plan <!-- How did you test these changes? --> - [ ] Unit tests added/updated - [ ] Integration tests added/updated - [ ] Passed `make installcheck` - [ ] Passed `make -C src/test installcheck-cbdb-parallel` ### Impact <!-- Remove sections that don't apply --> **Performance:** <!-- Any performance implications? --> **User-facing changes:** <!-- Any changes visible to users? --> **Dependencies:** <!-- New dependencies or version changes? --> ### Checklist - [ ] Followed [contribution guide](https://cloudberry.apache.org/contribute/code) - [ ] Added/updated documentation - [ ] Reviewed code for security implications - [ ] This PR contains AI-assisted code generation - [ ] Requested review from [cloudberry committers](https://github.com/orgs/apache/teams/cloudberry-committers) ### Additional Context <!-- Any other information that would help reviewers? Remove if none --> ### CI Skip Instructions <!-- To skip CI builds, add the appropriate CI skip identifier to your PR title. The identifier must: - Be in square brackets [] - Include the word "ci" and either "skip" or "no" - Only use for documentation-only changes or when absolutely necessary --> --- <!-- Join our community: - Mailing list: [[email protected]](https://lists.apache.org/[email protected]) (subscribe: [email protected]) - Discussions: https://github.com/apache/cloudberry/discussions --> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
