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https://issues.apache.org/jira/browse/DRILL-3921?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14953500#comment-14953500
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ASF GitHub Bot commented on DRILL-3921:
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Github user jacques-n commented on the pull request:
https://github.com/apache/drill/pull/197#issuecomment-147479176
Why does it take 48 seconds for planning?
> Hive LIMIT 1 queries take too long
> ----------------------------------
>
> Key: DRILL-3921
> URL: https://issues.apache.org/jira/browse/DRILL-3921
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Flow
> Reporter: Sudheesh Katkam
> Assignee: Sudheesh Katkam
>
> Fragment initialization on a Hive table (that is backed by a directory of
> many files) can take really long. This is evident through LIMIT 1 queries.
> The root cause is that the underlying reader in the HiveRecordReader is
> initialized when the ctor is called, rather than when setup is called.
> Two changes need to be made:
> 1) lazily initialize the underlying record reader in HiveRecordReader
> 2) allow for running a callable as a proxy user within an operator (through
> OperatorContext). This is required as initialization of the underlying record
> reader needs to be done as a proxy user (proxy for owner of the file).
> Previously, this was handled while creating the record batch tree.
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