MDEV-41220: GROUP_CONCAT(expr ORDER BY col) mis-sorts where col is NULL - #5704
Open
MikeWang000000 wants to merge 1 commit into
Open
MikeWang000000 wants to merge 1 commit into
MikeWang000000 wants to merge 1 commit into
Conversation
The sort keys were built from the record minus its NULL bytes, and the comparators never looked at the NULL bits, so a NULL ORDER BY value was compared against stale bytes left in the record by the previous row. Store the whole record, NULL bytes included, as the key, and let the comparators handle NULLs themselves. The now-redundant *_with_nulls variants and the helpers that selected between them are removed.
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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 sort keys were built from the record minus its NULL bytes, and the comparators never looked at the NULL bits, so a NULL ORDER BY value was compared against stale bytes left in the record by the previous row.
Store the whole record, NULL bytes included, as the key, and let the comparators handle NULLs themselves. The now-redundant *_with_nulls variants and the helpers that selected between them are removed.