Alex Behm has posted comments on this change.

Change subject: IMPALA-4303: Do not reset() qualifier of union operands.
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Patch Set 1:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/4963/1/fe/src/main/java/org/apache/impala/analysis/UnionStmt.java
File fe/src/main/java/org/apache/impala/analysis/UnionStmt.java:

Line 56:    * Contains a query statement and the all/distinct qualifier
> adapt or remove that last sentence, which is redundant anyway.
Done


Line 61:     // distinct propagation and unnesting that are needed after 
rewriting Subqueries.
> i don't understand the semantics of UnionStmt.reset() anymore. if we're try
Your summary seems correct to me. UnionStmt.reset() undoes all analysis state, 
except unnesting and distinct propagation.

There is no need to preserve distinctOperands_ and allOperands_ because 
operands_ also contains those after analysis.

A saner version of reset() would of course undo all changes made in analyze(). 
Unfortunately, that is rather difficult because analyze() does in-place 
modifications to the operands and even nested operands_ lists during unnesting, 
and also overwrites the original operands_.

Added comment to reset().


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Gerrit-MessageType: comment
Gerrit-Change-Id: I157bb0f08c4a94fd779487d7c23edd64a537a1f6
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Alex Behm <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
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