[main] Fix to #32023 - Case expressions may only be nested to level 10 when using SplitQuery() or ToList() inside projection. #32094
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
…using SplitQuery() or ToList() inside projection. Problem was that our SqlExpression simplifying visitor, when visiting ShapedQuery would only look into QueryExpression part. This makes sense in general as QueryExpression is where the SqlExpression is stored. However, for split query scenarios, we also have SqlExpression in the ShaperExpression (wrapped by RelationalSplitCollectionShaperExpression), and all the optimizations were not run on that SqlExpression piece, which in that case caused too deep CASE WHEN ELSE structure (that we normally optimize into flat CASE with multiple WHENs. Fix is to also visit ShaperExpression when performing post processing. Fixes #32023
roji
approved these changes
Oct 23, 2023
1 task
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Outdated suggestions cannot be applied.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.
Problem was that our SqlExpression simplifying visitor, when visiting ShapedQuery would only look into QueryExpression part. This makes sense in general as QueryExpression is where the SqlExpression is stored. However, for split query scenarios, we also have SqlExpression in the ShaperExpression (wrapped by RelationalSplitCollectionShaperExpression), and all the optimizations were not run on that SqlExpression piece, which in that case caused too deep CASE WHEN ELSE structure (that we normally optimize into flat CASE with multiple WHENs.
Fix is to also visit ShaperExpression when performing post processing.
Fixes #32023