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Posted to issues-all@impala.apache.org by "Tim Armstrong (JIRA)" <ji...@apache.org> on 2018/11/29 21:24:00 UTC
[jira] [Updated] (IMPALA-6754) Exchange node includes
FirstBatchArrivalWaitTime in summary
[ https://issues.apache.org/jira/browse/IMPALA-6754?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tim Armstrong updated IMPALA-6754:
----------------------------------
Labels: observability (was: )
> Exchange node includes FirstBatchArrivalWaitTime in summary
> -----------------------------------------------------------
>
> Key: IMPALA-6754
> URL: https://issues.apache.org/jira/browse/IMPALA-6754
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 2.11.0
> Reporter: Balazs Jeszenszky
> Assignee: Michael Ho
> Priority: Minor
> Labels: observability
>
> In the following execution summary:
> {code:java}
> Operator #Hosts Avg Time Max Time #Rows Est. #Rows Peak Mem Est. Peak Mem Detail
> -----------------------------------------------------------------------------------------------------------------------------------
> 15:AGGREGATE 1 141.556us 141.556us 1 1 20.00 KB 10.00 MB FINALIZE
> 14:EXCHANGE 1 2h46m 2h46m 1 1 0 0 UNPARTITIONED
> 09:AGGREGATE 1 16s442ms 16s442ms 1 1 768.00 KB 10.00 MB
> 08:HASH JOIN 1 1h38m 1h38m 2.63B -1 122.64 MB 2.00 GB LEFT OUTER JOIN, BROADCAST
> [...]
> {code}
> the timer for the EXCHANGE node is misleading. It's unlikely that sending a single row across network took so long, and individual counters confirm:
> {code:java}
> EXCHANGE_NODE (id=14):(Total: 2h46m, non-child: 2h46m, % non-child: 100.00%)
> - ConvertRowBatchTime: 901.000ns
> - PeakMemoryUsage: 0
> - RowsReturned: 1 (1)
> - RowsReturnedRate: 0
> DataStreamReceiver:
> - BytesReceived: 16.00 B (16)
> - DeserializeRowBatchTimer: 4.965us
> - FirstBatchArrivalWaitTime: 2h46m
> - PeakMemoryUsage: 4.01 KB (4104)
> - SendersBlockedTimer: 0.000ns
> - SendersBlockedTotalTimer(*): 0.000ns
> {code}
> In this case, the underlying joins took long (which is correctly reported in the rest of the profile).
> Exchange timers should reflect the time it took to transfer rows across network.
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