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Posted to issues@calcite.apache.org by "Haisheng Yuan (Jira)" <ji...@apache.org> on 2021/04/20 04:55:00 UTC
[jira] [Comment Edited] (CALCITE-4577) RelDigestWriter#done has
performance issue when node's inputs is large
[ https://issues.apache.org/jira/browse/CALCITE-4577?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17325474#comment-17325474 ]
Haisheng Yuan edited comment on CALCITE-4577 at 4/20/21, 4:54 AM:
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See comments in CALCITE-4578, since 1.24.0, the issue should not exist anymore.
was (Author: hyuan):
See comments in CALCITE-4578, since 1.24.0, the issue should exist anymore.
> RelDigestWriter#done has performance issue when node's inputs is large
> ----------------------------------------------------------------------
>
> Key: CALCITE-4577
> URL: https://issues.apache.org/jira/browse/CALCITE-4577
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Jiatao Tao
> Assignee: Jiatao Tao
> Priority: Critical
> Attachments: image-2021-04-11-16-53-35-466.png, image-2021-04-11-16-53-58-757.png
>
>
> Example like that: insert xxx VALUES (1, 'one'), (2, 'two'), (3, 'three')...(10000, 'ten thousand');
> It generates a Union node with 10000 inputs, and the performance is poor, here's the profile:
>
> !image-2021-04-11-16-53-58-757.png|width=735,height=109!
> A point that affects performance is the array copy of StringBuilder, current we just new StringBuilder with default capacity, my proposal is to consider the node's input size, like that(we can discuss the strategy):
> org.apache.calcite.rel.AbstractRelNode.RelDigestWriter#done
> {code:java}
> StringBuilder sb = new StringBuilder((values.size() + 1) * 16);{code}
> It's about 20% performance improvement and mem is more smooth.
>
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