HIVE-29249: RuntimeException in PlanModifierForASTConv.introduceDerivedTable for queries with self joins #6117
+47
−20
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
…edTable for queries with self joins The problem occurs when we need to introduce a derived table over the left input of the join but the input is already modified (newL) by the shuttle. Looking for the modified input in the join's children fails and raises an exception. Since we know which input needs to be replaced we can avoid the lookup mechanism in `introduceDerivedTable(RelNode, RelNode)` and build directly the new join operator via copy. To avoid unnecessary object creation bubling further up via the HiveRelShuttle mechansim we perform the copy *only* when one of the inputs is modified.
|
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 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Outdated suggestions cannot be applied.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.
What changes were proposed in this pull request?
introduceDerivedTable(RelNode)instead ofintroduceDerivedTable(RelNode,RelNode)to avoid the exception when the (left) input is already modified by the shuttle.SelfJoinHandler.Why are the changes needed?
The problem occurs when we need to introduce a derived table over the left input of the join but the input is already modified (newL) by the shuttle. Looking for the modified input in the join's children fails and raises an exception. Since we know which input needs to be replaced we can avoid the lookup mechanism in
introduceDerivedTable(RelNode, RelNode)and build directly the new join operator via copy.To avoid unnecessary object creation bubling further up via the HiveRelShuttle mechansim we perform the copy only when one of the inputs is modified.
Does this PR introduce any user-facing change?
No
How was this patch tested?