Hello Shant Hovsepian, Zoltan Borok-Nagy,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/16171
to look at the new patch set (#5).
Change subject: IMPALA-9949: fix SELECT list subqueries with HAVING/LIMIT
......................................................................
IMPALA-9949: fix SELECT list subqueries with HAVING/LIMIT
The patch for IMPALA-8954 failed to account for subqueries
that could produce < 1 row. SelectStmt.returnsSingleRow()
is confusing because it actually returns true if it
returns *at most* one row.
As a fix I split it into returnsExactlyOneRow() and
returnsAtMostOneRow(), then used returnsExactlyOneRow()
to determine if the subquery should instead be rewritten
into a LEFT OUTER JOIN, which produces the correct result.
CROSS JOIN is still preferred because it can be more freely
reordered during planning.
Testing:
* Added planner tests for a range of scenarios where it can
be rewritten as a CROSS JOIN and where it needs to be a LEFT
OUTER JOIN for correctness.
* Added some targeted end-to-end tests where the results were
previously incorrect. Checked the behaviour against Hive and
postgres.
Ran exhaustive tests.
Change-Id: I6034aedac776783bdc8cdb3a2df344e2b3662da6
---
M fe/src/main/java/org/apache/impala/analysis/Expr.java
M fe/src/main/java/org/apache/impala/analysis/SelectStmt.java
M fe/src/main/java/org/apache/impala/analysis/StmtRewriter.java
M fe/src/main/java/org/apache/impala/analysis/Subquery.java
M fe/src/main/java/org/apache/impala/analysis/TableRef.java
M fe/src/test/java/org/apache/impala/analysis/AnalyzeStmtsTest.java
M
testdata/workloads/functional-planner/queries/PlannerTest/subquery-rewrite.test
M testdata/workloads/functional-query/queries/QueryTest/subquery.test
8 files changed, 468 insertions(+), 26 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/71/16171/5
--
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I6034aedac776783bdc8cdb3a2df344e2b3662da6
Gerrit-Change-Number: 16171
Gerrit-PatchSet: 5
Gerrit-Owner: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Shant Hovsepian <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Zoltan Borok-Nagy <[email protected]>
