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:

(2 comments)

the current jenkins run is likely to fail, the fix is to rebase to get 
https://gerrit.cloudera.org/#/c/24898/

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@86
PS1, Line 86: The state and the array are allocated by 
FunctionContext::Allocate()
            :   // outside the reservation, so running short of this memory 
doesn't make the
            :   // aggregation spill (IMPALA-3304).
Would it be hard to do it within reservation?

Currently these aggregates can cause trouble, for example by using excessive 
memory during preaggregation. Reserving the worst case memory based on 
RESERVOIR_MAX_CAPACITY would allow limiting pre-agg and properly spill in the 
final aggregation. It may make some queries slower, but avoid OOM errors.


http://gerrit.cloudera.org:8080/#/c/24883/1/fe/src/main/java/org/apache/impala/planner/AggregationNode.java@1190
PS1, Line 1190: getFreePoolBytes
this is not aggregation specific, some more central class would be better place 
for the function IMO



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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: Sun, 20 Sep 2026 19:34:37 +0000
Gerrit-HasComments: Yes

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