Aman Sinha 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: (1 comment) 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) { > Yes, there is an assumption of uniform distribution (I should add a comment I went ahead and modified the hint to require a sampling percent be specified. This simplifies this whole calculation (just gets rid of it :) ) and I think is the best option because it makes the behavior predictable. Please compare the PS7 with PS6 to see the diffs. The hint is specified as [convert_limit_to_sample(5)] i.e percent in parenthesis (I chose parens instead of '=' because it is consistent with how TABLESAMPLE percent is specified and also because PlanHint.toString() already generates arguments wrapped in parens. -- 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: Sat, 05 Dec 2020 23:05:00 +0000 Gerrit-HasComments: Yes
