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Posted to issues-all@impala.apache.org by "Alex Rodoni (JIRA)" <ji...@apache.org> on 2018/08/30 18:19:00 UTC

[jira] [Updated] (IMPALA-5200) Profile timers not updated during long-running sort

     [ https://issues.apache.org/jira/browse/IMPALA-5200?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Alex Rodoni updated IMPALA-5200:
--------------------------------
    Docs Text:   (was: Workaround: slow sorts can be identified by looking at "Peak Mem" in the summary or "PeakMemoryUsage" in the profile. If a sort is consuming multiple GB of memory per host, it will likely spent a significant amount of time sorting the data.)

> Profile timers not updated during long-running sort
> ---------------------------------------------------
>
>                 Key: IMPALA-5200
>                 URL: https://issues.apache.org/jira/browse/IMPALA-5200
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Backend
>    Affects Versions: Impala 2.9.0
>            Reporter: Tim Armstrong
>            Priority: Minor
>              Labels: observability, ramp-up, supportability
>
> If you have a query plan with a long-running sort operation (e.g. minutes), the profile timers are not updated to reflect the time spent in the sort until the sort starts returning rows.
> E.g. this is a summary from a sort query that was running for a few hours (!). The summary was misleading and the "heat map" plan in the debug web UI is misleading - it showed the join as the "hot" operator. It would be ideal if we could somehow at least periodically update the time spent in the operator.
> {code}
> Operator              #Hosts   Avg Time   Max Time    #Rows  Est. #Rows   Peak Mem  Est. Peak Mem  Detail                   
> ----------------------------------------------------------------------------------------------------------------------------
> 05:MERGING-EXCHANGE        1    0.000ns    0.000ns        0     635.58M          0        -1.00 B  UNPARTITIONED            
> 03:SORT                    1    0.000ns    0.000ns        0     635.58M   47.86 GB      800.00 MB                           
> 02:HASH JOIN               1    4s859ms    4s859ms  771.02M     635.58M  162.11 MB       16.03 MB  INNER JOIN, BROADCAST    
> |--04:EXCHANGE             1   38.988ms   38.988ms  247.20K     247.20K          0              0  BROADCAST                
> |  01:SCAN HDFS            1    8s089ms    8s089ms  247.20K     247.20K    3.79 MB       32.00 MB  product b     
> 00:SCAN HDFS               1  209.997ms  209.997ms   15.09M     635.58M  185.27 MB      176.00 MB  sales a
> {code}
> http://community.cloudera.com/t5/Interactive-Short-cycle-SQL/Impala-join-query-running-slow



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