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https://issues.apache.org/jira/browse/HIVE-4239?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14564517#comment-14564517
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Carl Steinbach commented on HIVE-4239:
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A couple comments on the patch:
* Would you mind changing the name of the new configuration property to
'hive.driver.parallel.compilation'? The only reference to this config property
is located in the Driver class, and both Driver and SessionState predate
HiveServer2 by several years. Driver and SessionState were used by HiveServer1
and continue to be used by the HiveCli, and I know that there are at least a
couple third-party libraries out there that attempt to support concurrency by
scheduling queries across a pool of Driver objects. In other words, this
property changes the behavior of a class which is not part of HiveServer2, and
also has the potential to change the behavior of other user-facing interfaces
built on top of Driver which are also not part of HiveServer2. I also hope that
at some point the Driver and SessionState classes will go away completely, at
which point we can deprecate and remove this property, but only if it
references "driver".
* I think the docstring for the new property could use some wordsmithing:
"Whether to enable parallel compilation on HiveServer2. _Disable as a
workaround for future bugs._" The last sentence isn't going to inspire much
confidence in users about either the quality of the product or the development
team that produced it.
* In order to enable this feature by default I think we need to be pretty
confident that parallel compilation works. The additional parallel test
coverage included in this patch is a great start, but I think it falls well
short of being comprehensive. I mentioned in an earlier comment that code
already exists for running qfile tests in parallel on top of HiveServer2. Why
not re-enable this?
> Remove lock on compilation stage
> --------------------------------
>
> Key: HIVE-4239
> URL: https://issues.apache.org/jira/browse/HIVE-4239
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2, Query Processor
> Reporter: Carl Steinbach
> Assignee: Sergey Shelukhin
> Attachments: HIVE-4239.01.patch, HIVE-4239.patch
>
>
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