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https://issues.apache.org/jira/browse/HIVE-10937?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15010143#comment-15010143
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Sergey Shelukhin edited comment on HIVE-10937 at 11/18/15 3:33 AM:
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On the cluster, with one daemon and 3 threads each running 4 smaller TPCDS 200
queries in parallel (27, 55, 52, 96), with plans obviously not shared between
different instances of the same query, I see a plan is used on average 1.93
times (~15% of the plans are used more than twice, maximum is 9 times). That is
actually lower than I would have expected. In any case, this plan cache would
only be good for wide queries and/or small and/or busy clusters, where a query
would only get few executors per node and thus run sequentially and not in
parallel. In parallel the plan cannot be reused it looks like. I actually
wonder why...
was (Author: sershe):
On the cluster, with one daemon and 3 threads each running 4 smaller TPCDS 200
queries in parallel (27, 55, 52, 96), with plans obviously not shared between
different instances of the same query, I see a plan is used on average 1.93
times. That is actually lower than I would have expected. In any case, this
plan cache would only be good for wide queries and/or small and/or busy
clusters, where a query would only get few executors per node and thus run
sequentially and not in parallel. In parallel the plan cannot be reused it
looks like. I actually wonder why...
> LLAP: make ObjectCache for plans work properly in the daemon
> ------------------------------------------------------------
>
> Key: HIVE-10937
> URL: https://issues.apache.org/jira/browse/HIVE-10937
> Project: Hive
> Issue Type: Sub-task
> Components: llap
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Attachments: HIVE-10937.01.patch, HIVE-10937.02.patch,
> HIVE-10937.03.patch, HIVE-10937.04.patch, HIVE-10937.05.patch,
> HIVE-10937.patch
>
>
> There's perf hit otherwise, esp. when stupid planner creates 1009 reducers of
> 4Mb each.
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