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https://issues.apache.org/jira/browse/IMPALA-6279?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Philip Zeyliger resolved IMPALA-6279.
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Resolution: Not A Bug
Hi,
This sort of question is typically tackled on our user lists rather than the
bug tracker.
Thanks!
> concurrent performance is bad
> -----------------------------
>
> Key: IMPALA-6279
> URL: https://issues.apache.org/jira/browse/IMPALA-6279
> Project: IMPALA
> Issue Type: Story
> Components: Backend
> Affects Versions: Impala 2.7.0
> Reporter: Zhangyi Lu
> Priority: Critical
> Attachments: profile.txt, s1.png, s2.png
>
>
> Version: Impala Shell v2.7.0-cdh5.9.1 (24ad6df) built on Wed Jan 11 13:39:25
> PST 2017
> Impala daemon number: 7
> memory: 120G per daemon
> I ran a query in nonconcurrent mode. It took 19.56s
> When I ran the same query with other 31 queries concurrently it took 3
> minutes 7 seconds. The concurrent performance was reduced dramatically.
> I attached two screenshots of some key metrics. In attached screenshot
> s1.png. This query took 3min7s in total. But the threads network receive and
> send wait time are 1.7 hours and 1.2 hours respectively. And planning wait
> time is longer than when this query was executed in non-concurrent mode.
> Most of the fragments’ log of this query is like screenshot s2.png, you can
> see the sum of system and user thread time is far less than total wall clock
> time. That means wait time took an extreme high percent of total time.
> Could someone help point out why the thread network receive and send wait
> time are so long?
> Here I attached a full profile of this query for your reference.
> Thanks.
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