Use selectivity in LookupJoin cost estimate #3099
Open
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
fulghum
reviewed
Jul 16, 2025
There was a problem hiding this comment.
I think this generally makes sense. We should dig into the plan changes deeper and make sure we think they're still correct. It would be ideal to measure the execution time of some of the changed query plans and spot check they they are actually faster with the lookup joins.
…server into angela/pk_join
- Updated ExpectedPlan, ExpectedEstimates, and ExpectedAnalysis sections - Changed MergeJoin to SemiLookupJoin with simplified structure - Reduced cost estimates from 3300.000 to 2300.000 - Copied actual test output to replace expected output - Reduced test failures from 838 to 832 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>
- Applied cost-only automation script (28 improvements) - Updated LeftOuterMergeJoin to LeftOuterLookupJoin (partial) - Total reduction: 34 test failures fixed - Continue systematically until zero failures 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>
…o angela/pk_join
…server into angela/pk_join
…o angela/pk_join
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Outdated suggestions cannot be applied.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.
Fixes dolthub/dolt#9520
Our previous LookupJoin cost estimate was not taking selectivity, the expected proportion of right-hand side rows that satisfy the join condition for each row from the left-hand side, into account, causing the cost estimate for LookupJoins to be too high. This was causing queries to be slow because LookupJoins were not getting picked when they should have.
Failing Dolt test because costs are different now. Will fix in bump PR