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https://issues.apache.org/jira/browse/HIVE-8760?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14200852#comment-14200852
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Gopal V commented on HIVE-8760:
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Immutable structures are prudent from an API design stand-point - copying
always to get to a shared-nothing model potentially breaks anyone who relied on
synchronization on that object elsewhere.
The stability impact of copying is currently invisible and unknown, but
eventually a lot of System.identityHashcode is applied to debug those and
System.err, because LOG.info() is synchronized.
The performance impact of however is well known (as quoted earlier). The core
API issue over-all for me is that we don't have immutable Conf objects - I keep
hitting these {{new Configuration()}} perf issues (track HADOOP-11223 for the
impact on HDFS).
At the very least, I know the stability impact of copying in one Hook, the
surface is rather narrow for that problem to trace through (i.e "ship
Hook2.java, Hook3.java etc and test them without rebuilding all of hive").
On top of it, the biggest user of Hooks seems to be itests (which ships
something like 20 single thread hooks). You'll be slowing down all of them, all
the time.
> Pass a copy of HiveConf to hooks
> --------------------------------
>
> Key: HIVE-8760
> URL: https://issues.apache.org/jira/browse/HIVE-8760
> Project: Hive
> Issue Type: Bug
> Components: Configuration
> Affects Versions: 0.13.0, 0.14.0
> Reporter: Ashutosh Chauhan
> Assignee: Ashutosh Chauhan
> Attachments: HIVE-8760.patch
>
>
> because hadoop's {{Configuration}} is not thread-safe
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