Fix force_parallel_mode to work as intended. #1287
Draft
Conversation
This file contains hidden or 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
The force_parallel_mode GUC is meant to facilitate testing of parallel query plans, but it currently allows non-parallel plans to win even when force_parallel_mode is enabled. This behavior makes it difficult to debug parallel plans as intended. Correct the behavior for testing purposes. Authored-by: Zhang Mingli [email protected]
yjhjstz
reviewed
Aug 3, 2025
| Path *cheapest_partial_path; | ||
| cheapest_partial_path = linitial(final_rel->partial_pathlist); | ||
| if (force_parallel_mode == FORCE_PARALLEL_ON) | ||
| final_rel->pathlist = NIL; |
Member
There was a problem hiding this comment.
if partial_pathlist == NIL，should not final_rel->pathlist = NIL; ?
Contributor
Author
There was a problem hiding this comment.
pathlist can not be empty- this will trigger a 'could not derive a plan for query' failure.
Contributor
Author
|
This PR opened a whole can of worms. Just skimming through, there are a bunch of wrong results. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
The force_parallel_mode GUC is meant to facilitate testing of parallel query plans, but it currently allows non-parallel plans to win even when force_parallel_mode is enabled.
This behavior makes it difficult to debug parallel plans as intended.
Correct the behavior for testing purposes.
Authored-by: Zhang Mingli [email protected]
Fixes #ISSUE_Number
What does this PR do?
Type of Change
Breaking Changes
Test Plan
make installcheckmake -C src/test installcheck-cbdb-parallelImpact
Performance:
User-facing changes:
Dependencies:
Checklist
Additional Context
CI Skip Instructions