HIVE-28222: Ambiguous table alias exception for queries with self joins #5998
+200
−16
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
kasakrisz
reviewed
Jul 30, 2025
| @@ -123,29 +127,35 @@ public static RelNode convertOpTree(RelNode rel, List<FieldSchema> resultSchema, | |||
| return newTopNode; | |||
| } | |||
|
|
|||
| private static String getTblAlias(RelNode rel) { | |||
| private static class AliasCollector extends RelHomogeneousShuttle { | |||
| List<String> aliases = new ArrayList<>(); | |||
There was a problem hiding this comment.
What happens when accept is called more than once on the same instance ? Is this list reseted before each?
There was a problem hiding this comment.
I discovered some issues with the previous code so I reworked the approach and force-pushed a new version. Apologies for rebasing and squashing, I haven't seen your comments before pushing the new version.
There was a problem hiding this comment.
No worries. Please let me know if you need another review.
Some queries that contain joins of the same table more than twice fail during compilation while trying to transform the optimized AST (obtained from CBO) to an Operator tree. The "Ambiguous table alias" exception is raised when a HiveJoin contains the same table scan multiple times (without an interleaving project) cause the generated AST is ambiguous.
|
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Outdated suggestions cannot be applied.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 changes were proposed in this pull request?
Why are the changes needed?
Some queries that contain joins of the same table more than twice fail during compilation while trying to transform the optimized AST (obtained from CBO) to an Operator tree. The "Ambiguous table alias" exception is raised when a HiveJoin contains the same table scan multiple times (without an interleaving project) cause the generated AST is ambiguous.
Does this PR introduce any user-facing change?
No.
How was this patch tested?