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https://issues.apache.org/jira/browse/HIVE-10191?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14729463#comment-14729463
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Prasanth Jayachandran commented on HIVE-10191:
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[~gopalv] We should document the impact of this change on the
hive.exec.orc.memory.pool for multiple threaded writers writing separately to
its own orc file.
> ORC: Cleanup writer per-row synchronization
> -------------------------------------------
>
> Key: HIVE-10191
> URL: https://issues.apache.org/jira/browse/HIVE-10191
> Project: Hive
> Issue Type: Bug
> Components: File Formats
> Affects Versions: 1.2.0
> Reporter: Gopal V
> Assignee: Gopal V
> Labels: TODOC1.3
> Fix For: 1.3.0, 2.0.0
>
> Attachments: HIVE-10191.1.patch, HIVE-10191.2.patch,
> HIVE-10191.3.patch, HIVE-10191.4.patch, HIVE-10191.5.patch
>
>
> ORC writers were originally meant to be thread-safe, but in the present day
> implementation each ORC writer is entirely share-nothing which converts most
> of the synchronized blocks in ORC as entirely uncontested locks.
> These uncontested locks prevent the JVM from inlining/optimizing these
> methods, while adding no extra thread-safety to the ORC writers.
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