Thomas Tauber-Marshall has uploaded a new change for review.

  http://gerrit.cloudera.org:8080/6653

Change subject: IMPALA-5125: SimplifyConditionalsRule incorrectly handles 
aggregates
......................................................................

IMPALA-5125: SimplifyConditionalsRule incorrectly handles aggregates

This patch addresses 3 issues:
- SelectList.reset didn't properly reset some of its members, though
  they're documented as needing to be reset. This was causing a crash
  when the Planner attempted to make an aggregation node for an agg
  function that had been eliminated by expr rewriting. While I'm here,
  I added reseting of all of SelectList's members that need to be reset,
  and fixed the documentation of one member that shouldn't be reset.
- SimplifyConditionalsRule was changing the meaning of queries that
  contains agg functions, e.g. because "select if(true, 0, sum(id))"
  is not equivalent to "select 0". The fix is to not return the simplfied
  expr if it removes all aggregates.
- ExprRewriteRulesTest was performing rewrites on the result exprs of the
  SelectStmt, which causes problems if the result exprs have been
  substituted. In normal query execution, we don't rewrite the result exprs
  anyways, so the fix is to match normal query execution and rewrite the select
  list exprs.

Testing:
- Added e2e test to exprs.test.
- Added unit test to ExprRewriteRulesTest.

Change-Id: Ic20b1621753980b47a612e0885804363b733f6da
---
M fe/src/main/java/org/apache/impala/analysis/SelectStmt.java
M fe/src/main/java/org/apache/impala/rewrite/SimplifyConditionalsRule.java
M fe/src/test/java/org/apache/impala/analysis/ExprRewriteRulesTest.java
M testdata/workloads/functional-query/queries/QueryTest/exprs.test
4 files changed, 37 insertions(+), 10 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/53/6653/1
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ic20b1621753980b47a612e0885804363b733f6da
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Thomas Tauber-Marshall <[email protected]>

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