Qifan Chen has posted comments on this change. ( http://gerrit.cloudera.org:8080/16792 )
Change subject: IMPALA-10360: Allow simple limit to be treated as sampling hint ...................................................................... Patch Set 7: (3 comments) Looks good! http://gerrit.cloudera.org:8080/#/c/16792/5/fe/src/main/java/org/apache/impala/analysis/SelectStmt.java File fe/src/main/java/org/apache/impala/analysis/SelectStmt.java: http://gerrit.cloudera.org:8080/#/c/16792/5/fe/src/main/java/org/apache/impala/analysis/SelectStmt.java@223 PS5, Line 223: // for single table query blocks, limit push > We cannot remove this because as I mentioned in a previous comment (patchse Little bit of confusion here for case 1. Since no convert_limit_to_sample hint is available, I thought we will not apply the limit to sample optimization. Note in the commit message, it says the hint is needed: "If this hint is attached to a table either in the main query block or within a view/subquery and simple limit optimization conditions are satisfied (according to IMPALA-10314), the limit is converted to a table sample" http://gerrit.cloudera.org:8080/#/c/16792/2/fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java File fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java: http://gerrit.cloudera.org:8080/#/c/16792/2/fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java@209 PS2, Line 209: f.setTableSampleCl > I haven't looked into why the past decision was to only support whole numbe Done http://gerrit.cloudera.org:8080/#/c/16792/5/fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java File fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java: http://gerrit.cloudera.org:8080/#/c/16792/5/fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java@217 PS5, Line 217: partitions) { > I went ahead and modified the hint to require a sampling percent be specifi Sounds good to me! -- To view, visit http://gerrit.cloudera.org:8080/16792 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ife05a5343c913006f7659949b327b63d3f10c04b Gerrit-Change-Number: 16792 Gerrit-PatchSet: 7 Gerrit-Owner: Aman Sinha <amsi...@cloudera.com> Gerrit-Reviewer: Aman Sinha <amsi...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Qifan Chen <qc...@cloudera.com> Gerrit-Reviewer: Shant Hovsepian <sh...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Comment-Date: Mon, 07 Dec 2020 16:26:52 +0000 Gerrit-HasComments: Yes
