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: Code-Review+1 (2 comments) Thanks! 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 > I am doing that check in HdfsPartitionPruner.pruneForSimpleLimit() line #20 Okay. That check will do the job. Thanks for pointing it out. http://gerrit.cloudera.org:8080/#/c/16792/7/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/16792/7/fe/src/main/java/org/apache/impala/planner/HdfsPartitionPruner.java@208 PS7, Line 208: tblRef.hasConvertLimitToSampleHint() We may need to document the case where the sample rate may be too small. For example, the same rate is 1 on a 1000 row table, and the limit value is 500. Understand it is a user mistake now. -- 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 <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Qifan Chen <[email protected]> Gerrit-Reviewer: Shant Hovsepian <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Comment-Date: Tue, 08 Dec 2020 03:57:17 +0000 Gerrit-HasComments: Yes
