[Impala-ASF-CR] IMPALA-7942 (part 2): Add query hints for predicate selectivities

["wangsheng (Code Review)" <ge...@cloudera.org>]

wangsheng has uploaded a new patch set (#10). ( http://gerrit.cloudera.org:8080/18023 )

Change subject: IMPALA-7942 (part 2): Add query hints for predicate selectivities
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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. Maybe in the future,
we can use histograms to get more precise query plan.

This patch adds another query hints: 'SELECTIVITY', we can use this
hint to original selectivity computing.

Format like this:

  select col from t where (a=1) /* +SELECTIVITY(0.5) */;

Besides, this hint is also valid for compound predicate like this:

  select col from t where (a=1 and b=2) /* +SELECTIVITY(0.5) */;

But pay attention, if we want to use 'SELECTIVITY' hint for predicate,
we need to wrap the predicate by braket, even for single binary
predicate.

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, 334 insertions(+), 5 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/23/18023/10
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I2776b9bbd878b8a21d9c866b400140a454f59e1b
Gerrit-Change-Number: 18023
Gerrit-PatchSet: 10
Gerrit-Owner: wangsheng <sk...@163.com>
Gerrit-Reviewer: Amogh Margoor <am...@gmail.com>
Gerrit-Reviewer: Fucun Chu <ch...@hotmail.com>
Gerrit-Reviewer: Impala Public Jenkins <im...@cloudera.com>
Gerrit-Reviewer: Qifan Chen <qf...@hotmail.com>
Gerrit-Reviewer: Quanlong Huang <hu...@gmail.com>
Gerrit-Reviewer: Zoltan Borok-Nagy <bo...@cloudera.com>
Gerrit-Reviewer: wangsheng <sk...@163.com>