Thomas Tauber-Marshall has uploaded a new change for review. http://gerrit.cloudera.org:8080/7567
Change subject: IMPALA-5725: coalesce() with outer join incorrectly rewritten ...................................................................... IMPALA-5725: coalesce() with outer join incorrectly rewritten A recent change, IMPALA-5016, added an expr rewrite rule to simplfy coalesce(). This rule eliminates the coalesce() when its first parameter (that isn't constant null) is a SlotRef pointing to a SlotDescriptor that is non-nullable (for example because it is from a non-nullable Kudu column or because it is from an HDFS partition column with no null partitions), under the assumption that the SlotRef could never have a null value. This assumption is violated when the SlotRef is the output of an outer join, leading to incorrect results being returned. The problem is that the nullability of a SlotDescriptor (which determines whether there is a null indicator bit in the tuple for that slot) is a slightly different property than the nullability of a SlotRef pointing to that SlotDescriptor (since the SlotRef can still be NULL if the entire tuple is NULL). This patch removes the portion of the rewrite rule that considers the nullability of the SlotDescriptor. This means that we're missing out on some optimizations opportunities and we should revisit this in a way that works with outer joins (IMPALA-5753) Testing: - Updated FE tests. - Added regression tests to exprs.test Change-Id: I1ca6df949f9d416ab207016236dbcb5886295337 --- M fe/src/main/java/org/apache/impala/analysis/SlotDescriptor.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, 30 insertions(+), 43 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/67/7567/1 -- To view, visit http://gerrit.cloudera.org:8080/7567 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: newchange Gerrit-Change-Id: I1ca6df949f9d416ab207016236dbcb5886295337 Gerrit-PatchSet: 1 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Thomas Tauber-Marshall <[email protected]>
