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From "Dan Hecht (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5160: adjust spill buffer size based on planner estimates
Date Tue, 30 May 2017 22:37:17 GMT
Dan Hecht has posted comments on this change.

Change subject: IMPALA-5160: adjust spill buffer size based on planner estimates
......................................................................


Patch Set 6:

> I updated the patchset to use explain_level EXTENDED for TPC-H and
 > TPC-DS. This doesn't enable the spill buffer size optimisation for
 > those test, but you can inspect 'mem-estimate' to get a rough idea
 > of what the reservation would be with the new code.
 > 
 > It looks like for the scale factor 1 TPC-H and TPC-DS most joins
 > would have their reservation scaled down, since mem-estimate <<< 17
 > * 2MB buffers.

But then the question is does the scaled down reservation impact perf or cause more spilling?

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Gerrit-MessageType: comment
Gerrit-Change-Id: I57b5b4c528325d478c8a9b834a6bc5dedab54b5b
Gerrit-PatchSet: 6
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: No

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