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https://issues.apache.org/jira/browse/HIVE-10940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14609085#comment-14609085
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Gunther Hagleitner commented on HIVE-10940:
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This patch doesn't really work for 2 reasons:
* It serializes the same or similar objects unnecessarily multiple times
during planning.
* It ooms in dpp cases, because the expr references a reduce sink.
> HiveInputFormat::pushFilters serializes PPD objects for each getRecordReader
> call
> ---------------------------------------------------------------------------------
>
> Key: HIVE-10940
> URL: https://issues.apache.org/jira/browse/HIVE-10940
> Project: Hive
> Issue Type: Bug
> Components: File Formats
> Affects Versions: 1.2.0
> Reporter: Gopal V
> Assignee: Sergey Shelukhin
> Fix For: 2.0.0
>
> Attachments: HIVE-10940.01.patch, HIVE-10940.patch
>
>
> {code}
> String filterText = filterExpr.getExprString();
> String filterExprSerialized = Utilities.serializeExpression(filterExpr);
> {code}
> the serializeExpression initializes Kryo and produces a new packed object for
> every split.
> HiveInputFormat::getRecordReader -> pushProjectionAndFilters -> pushFilters.
> And Kryo is very slow to do this for a large filter clause.
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