planner: prune duplicate expr in sort #20325
Merged
Conversation
This file contains 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
|
|
zz-jason
reviewed
Oct 2, 2020
zz-jason
reviewed
Oct 2, 2020
ti-srebot
approved these changes
Oct 2, 2020
|
/merge |
ti-srebot
added
the
status/can-merge
|
/run-all-tests |
|
@mightyguava merge failed. |
|
/run-sqllogic-test |
|
cherry pick to release-4.0 in PR #20333 |
ti-srebot
pushed a commit
to ti-srebot/tidb
that referenced
this pull request
Oct 3, 2020
Signed-off-by: ti-srebot <ti-srebot@pingcap.com>
ti-srebot
added a commit
that referenced
this pull request
Oct 13, 2020
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
What problem does this PR solve?
Issue Number: close #20322
Problem Summary: Duplicated ORDER BY condition causes bad execution plan
What is changed and how it works?
What's Changed: Duplicated expressions are pruned from the logical plan during the preprocessing phase
How it Works: Iterate through the ByItems in the sort plan in order and prune columns that have already been seen. Any duplicates found are always noop sort steps.
Check List
Tests
Side effects
Release note