wangsheng has uploaded a new patch set (#7). ( http://gerrit.cloudera.org:8080/18829 )
Change subject: IMPALA-7942 (part 1): Add query hints for table cardinalities ...................................................................... IMPALA-7942 (part 1): Add query hints for table cardinalities Currently, we run 'COMPUTE STATS' command to compute table stats which is very useful for query planning. Without these stats, a query plan may not be optimal. However, these stats may not be available, up to date, or valid. To workaround this problem, this patch adds a new query hint: 'TABLE_NUM_ROWS', We can use this new hint after a hdfs or kudu table in query like this: * select col from t /* +TABLE_NUM_ROWS(1000) */; If set, Impala will use this value as table scanned rows when table no stats or has corrput stats. This hint value will not valid if table stats is normal. Testing: - Added new fe test in 'PlannerTest' - Added new fe test in 'AnalyzeStmtsTest' for negative cases Change-Id: I9f0c773f4e67782a1428db64062f68afbd257af7 --- M fe/src/main/java/org/apache/impala/analysis/TableRef.java M fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java M fe/src/main/java/org/apache/impala/planner/KuduScanNode.java M fe/src/main/java/org/apache/impala/planner/ScanNode.java M fe/src/main/java/org/apache/impala/planner/SingleNodePlanner.java 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/table-cardinality-hint.test 8 files changed, 164 insertions(+), 10 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/29/18829/7 -- To view, visit http://gerrit.cloudera.org:8080/18829 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: newpatchset Gerrit-Change-Id: I9f0c773f4e67782a1428db64062f68afbd257af7 Gerrit-Change-Number: 18829 Gerrit-PatchSet: 7 Gerrit-Owner: wangsheng <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Fang-Yu Rao <[email protected]> Gerrit-Reviewer: Fucun Chu <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Qifan Chen <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: wangsheng <[email protected]>
