Csaba Ringhofer has posted comments on this change. ( http://gerrit.cloudera.org:8080/24883 )
Change subject: IMPALA-13052: Estimate reservoir sample memory in aggregations ...................................................................... Patch Set 1: (1 comment) http://gerrit.cloudera.org:8080/#/c/24883/1/fe/src/main/java/org/apache/impala/planner/AggregationNode.java File fe/src/main/java/org/apache/impala/planner/AggregationNode.java: http://gerrit.cloudera.org:8080/#/c/24883/1/fe/src/main/java/org/apache/impala/planner/AggregationNode.java@88 PS1, Line 88: // aggregation spill (IMPALA-3304). > Not in this change: it needs a backend change. Reserving the worst case cos Ack. My assumption was that in most use cases the full capacity of 20000 is used, otherwise what's the point in using reservoir sampling? But I agree, if actually only few rows are in a group, then it could lead to lot of wasteful spilling. -- To view, visit http://gerrit.cloudera.org:8080/24883 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Id6eec3daf7fea9b027ff0be9c95c6ee5a3cf323d Gerrit-Change-Number: 24883 Gerrit-PatchSet: 1 Gerrit-Owner: Aleksandr Efimov <[email protected]> Gerrit-Reviewer: Aleksandr Efimov <[email protected]> Gerrit-Reviewer: Csaba Ringhofer <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Riza Suminto <[email protected]> Gerrit-Comment-Date: Wed, 23 Sep 2026 08:52:02 +0000 Gerrit-HasComments: Yes
