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Posted to issues@impala.apache.org by "Tim Armstrong (Jira)" <ji...@apache.org> on 2019/11/14 21:15:00 UTC
[jira] [Resolved] (IMPALA-9128) Improve debugging for slow sends in
KrpcDataStreamSender
[ https://issues.apache.org/jira/browse/IMPALA-9128?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tim Armstrong resolved IMPALA-9128.
-----------------------------------
Fix Version/s: Impala 3.4.0
Resolution: Fixed
> Improve debugging for slow sends in KrpcDataStreamSender
> --------------------------------------------------------
>
> Key: IMPALA-9128
> URL: https://issues.apache.org/jira/browse/IMPALA-9128
> Project: IMPALA
> Issue Type: Bug
> Components: Distributed Exec
> Reporter: Tim Armstrong
> Assignee: Tim Armstrong
> Priority: Major
> Labels: observability
> Fix For: Impala 3.4.0
>
>
> I'm trying to debug a problem that appears to be caused by a slow RPC:
> {noformat}
> Fragment F00
> Instance 754fc21ba4744310:d58fd04200000020 (host=xxxxxxxxx)
> Hdfs split stats (<volume id>:<# splits>/<split lengths>): 0:1/120.48 MB
> - AverageThreadTokens: 1.00 (1.0)
> - BloomFilterBytes: 0 B (0)
> - InactiveTotalTime: 0ns (0)
> - PeakMemoryUsage: 3.2 MiB (3337546)
> - PeakReservation: 2.0 MiB (2097152)
> - PeakUsedReservation: 0 B (0)
> - PerHostPeakMemUsage: 6.7 MiB (6987376)
> - RowsProduced: 7 (7)
> - TotalNetworkReceiveTime: 0ns (0)
> - TotalNetworkSendTime: 3.6m (215354065071)
> - TotalStorageWaitTime: 4ms (4552708)
> - TotalThreadsInvoluntaryContextSwitches: 2 (2)
> - TotalThreadsTotalWallClockTime: 3.6m (215924079474)
> - TotalThreadsSysTime: 24ms (24386000)
> - TotalThreadsUserTime: 505ms (505714000)
> - TotalThreadsVoluntaryContextSwitches: 3,623 (3623)
> - TotalTime: 3.6m (215801961705)
> Fragment Instance Lifecycle Event Timeline
> Prepare Finished: 1ms (1812344)
> Open Finished: 322ms (322905753)
> First Batch Produced: 447ms (447050377)
> First Batch Sent: 447ms (447054546)
> ExecInternal Finished: 3.6m (215802284852)
> Buffer pool
> - AllocTime: 0ns (0)
> - CumulativeAllocationBytes: 0 B (0)
> - CumulativeAllocations: 0 (0)
> - InactiveTotalTime: 0ns (0)
> - PeakReservation: 0 B (0)
> - PeakUnpinnedBytes: 0 B (0)
> - PeakUsedReservation: 0 B (0)
> - ReadIoBytes: 0 B (0)
> - ReadIoOps: 0 (0)
> - ReadIoWaitTime: 0ns (0)
> - ReservationLimit: 0 B (0)
> - TotalTime: 0ns (0)
> - WriteIoBytes: 0 B (0)
> - WriteIoOps: 0 (0)
> - WriteIoWaitTime: 0ns (0)
> Fragment Instance Lifecycle Timings
> - ExecTime: 3.6m (215479380267)
> - ExecTreeExecTime: 124ms (124299400)
> - InactiveTotalTime: 0ns (0)
> - OpenTime: 321ms (321088906)
> - ExecTreeOpenTime: 572.04us (572045)
> - PrepareTime: 1ms (1426412)
> - ExecTreePrepareTime: 233.32us (233318)
> - TotalTime: 0ns (0)
> KrpcDataStreamSender (dst_id=3)
> - EosSent: 58 (58)
> - InactiveTotalTime: 3.6m (215354085858)
> - PeakMemoryUsage: 464.4 KiB (475504)
> - RowsSent: 7 (7)
> - RpcFailure: 0 (0)
> - RpcRetry: 0 (0)
> - SerializeBatchTime: 99.87us (99867)
> - TotalBytesSent: 207 B (207)
> - TotalTime: 3.6m (215355336381)
> - UncompressedRowBatchSize: 267 B (267)
> {noformat}
> We should add some diagnostics that will allow us to figure out which RPCs are slow and whether there's a pattern about which host is the problem. E.g. maybe we should log if the RPC time exceeds a configured threshold.
> It may also be useful to include some stats about the wait time, e.g. a histogram of the wait times, so that we can see if it's an outlier or general slowness.
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