C++: Fix join order in CommentedOutCode #243
Merged
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
After the recent inlining of `unresolveElement`, the join order in `CommentedOutCode` became a problem. The join orderer was tempted to join the two `hasLocationInfo` calls first because they had one column in common. With this commit, they have no columns in common. It follows from the other predicates in the same file that this column would be the same, so there is no need to assert it in this predicate and risk that the join orderer uses that information. On Wireshark, the `CommentBlock::hasLocationInfo` predicate goes from taking 2m2s to taking 180ms. The query produces the same 7,448 alerts.
ian-semmle
approved these changes
Sep 27, 2018
smowton
pushed a commit
to smowton/codeql
that referenced
this pull request
Feb 7, 2022
Fix merge conflict
MathiasVP
pushed a commit
to MathiasVP/ql
that referenced
this pull request
Aug 10, 2025
fix powershell qhelp files
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 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Outdated suggestions cannot be applied.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.
After the recent inlining of
unresolveElement, the join order inCommentedOutCodebecame a problem. The join orderer was tempted to join the twohasLocationInfocalls first because they had one column in common. With this commit, they have no columns in common. It follows from the other predicates in the same file that this column would be the same, so there is no need to assert it in this predicate and risk that the join orderer uses that information.On Wireshark, the
CommentBlock::hasLocationInfopredicate goes from taking 2m2s to taking 180ms. The query produces the same 7,448 alerts.