wangsheng has uploaded a new patch set (#26). ( http://gerrit.cloudera.org:8080/18023 )
Change subject: IMPALA-7942 (part 2): Add query hints for predicate selectivities ...................................................................... IMPALA-7942 (part 2): Add query hints for predicate selectivities Currently, Impala only uses simple estimation to compute selectivity for some predicates, and this may lead to worse query plan due to CBO. Hence, we add new hints to reduce such errors. This patch adds a new query hints: 'SELECTIVITY', we can use this hint to original selectivity computing. The parser will interpret expressions wrapped in () followed by a C-style /* comment */ as a predicate hint. The predicate hint currently supports +SELECTIVITY(f) where 'f' is a positive floating point number to use as the selectivity for the preceding expression. Single predicate example: select col from t where (a=1) /* +SELECTIVITY(0.5) */; Compound Predicate Example: select col from t where (a=1 and b=2) /* +SELECTIVITY(0.5) */; Testing: - Added new fe tests in 'PlannerTest' - Added new fe tests in 'AnalyzeStmtsTest' for negative cases Change-Id: I2776b9bbd878b8a21d9c866b400140a454f59e1b --- M fe/src/main/cup/sql-parser.cup M fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java M fe/src/main/java/org/apache/impala/analysis/CompoundPredicate.java M fe/src/main/java/org/apache/impala/analysis/Expr.java M fe/src/main/java/org/apache/impala/analysis/InPredicate.java M fe/src/main/java/org/apache/impala/analysis/IsNullPredicate.java M fe/src/main/java/org/apache/impala/analysis/Predicate.java M fe/src/main/java/org/apache/impala/rewrite/BetweenToCompoundRule.java M fe/src/main/jflex/sql-scanner.flex M fe/src/test/java/org/apache/impala/analysis/AnalyzeStmtsTest.java M fe/src/test/java/org/apache/impala/planner/PlannerTest.java A testdata/workloads/functional-planner/queries/PlannerTest/predicate-selectivity-hint.test 12 files changed, 446 insertions(+), 6 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/23/18023/26 -- To view, visit http://gerrit.cloudera.org:8080/18023 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: newpatchset Gerrit-Change-Id: I2776b9bbd878b8a21d9c866b400140a454f59e1b Gerrit-Change-Number: 18023 Gerrit-PatchSet: 26 Gerrit-Owner: wangsheng <sky...@163.com> Gerrit-Reviewer: Amogh Margoor <amarg...@gmail.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Kurt Deschler <kdesc...@cloudera.com> Gerrit-Reviewer: Qifan Chen <qfc...@hotmail.com> Gerrit-Reviewer: Quanlong Huang <huangquanl...@gmail.com> Gerrit-Reviewer: Xiang Yang <yx91...@126.com> Gerrit-Reviewer: Zoltan Borok-Nagy <borokna...@cloudera.com> Gerrit-Reviewer: wangsheng <sky...@163.com>
