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https://issues.apache.org/jira/browse/MAPREDUCE-6684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15260817#comment-15260817
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Karthik Kambatla commented on MAPREDUCE-6684:
---------------------------------------------
bq. If ATSv2 is going to completely replace the JHS
While the need for writing out and copying/parsing jhist files might be
replaced by accesses to ATS, I would think the JHS itself would stick around to
provide MR-specific UI it does today. Not sure if ATS would be able to expose
the right abstractions for each framework to plugin the appropriate UI.
bq. Because it is complex with lots of race conditions to work through I worry
we can introduce new subtle bugs when it's rewritten.
bq. But I think a lot of the races are inherent in the problem, some users are
trying to read data and get a consistent view of it while at the same time the
data is moving from one place to another.
Agree with you both. Given it is mostly stable barring the occasional
inefficiency, we should probably just leave it alone. If we run into more
issues around this, may be we could revisit cleaning it up.
In terms of potential cleanups:
# When fetching information regarding one job, we scan the entire intermediate
directory potentially triggering other moves. Instead, it would be nice if it
looks only for that specific job. And, if that very file is being moved, wait
for the move to complete. That way, we don't have to think about a read thread
accessing files corresponding to other jobs.
# HistoryFileManager is rather long - moving out some of the inner classes
might make for cleaner abstractions and more explicit locking where needed for
readability.
# I keep thinking about doing the move in a separate class/thread and some way
for the read threads to communicate with this move thread, but that might just
result in more complicated code. I will have to poke around to figure out which
way is simpler; don't think I can get it to anytime soon though.
> High contention on scanning of user directory under immediate_done in Job
> History Server
> ----------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-6684
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6684
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobhistoryserver
> Affects Versions: 2.7.0
> Reporter: Haibo Chen
> Assignee: Haibo Chen
> Priority: Critical
> Attachments: jhs-jstacks-service-monitor-running.tar.gz,
> jhs-jstacks-service-monitor-stopped.tar.gz
>
>
> HistoryFileManager.scanIntermediateDirectory() in JHS acquires a lock on each
> user directory it tries to scan (move or delete files under the user
> directory as necessary). This method is called in a thread in JobHistory that
> performs periodical scanning of intermediate directory, and can also be
> called by web server threads for each Web API call made by a JHS client. In
> cases where there are many concurrent Web API calls/connections to JHS, all
> but one thread are blocked on the lock on the user directory. Eventually,
> client connects will time out, but the threads in JHS will not be killed and
> leave a lot of TCP connections in CLOSE_WAIT state.
> {noformat}
> [systest@vb1120 ~]$ sudo netstat -nap | grep 63729 | sort -k 4
> tcp 0 0 10.17.202.19:10020 0.0.0.0:*
> LISTEN 63729/java
> tcp 0 0 10.17.202.19:10020 10.17.198.30:33010
> ESTABLISHED 63729/java
> tcp 0 0 10.17.202.19:10020 10.17.200.30:33980
> ESTABLISHED 63729/java
> tcp 0 0 10.17.202.19:10020 10.17.202.10:59625
> ESTABLISHED 63729/java
> tcp 0 0 10.17.202.19:10020 10.17.202.13:35765
> ESTABLISHED 63729/java
> tcp 0 0 10.17.202.19:10033 0.0.0.0:*
> LISTEN 63729/java
> tcp 0 0 10.17.202.19:19888 0.0.0.0:*
> LISTEN 63729/java
> tcp 0 0 10.17.202.19:19888 10.17.198.30:35103
> ESTABLISHED 63729/java
> tcp 277 0 10.17.202.19:19888 10.17.198.30:43670
> ESTABLISHED 63729/java
> tcp 0 0 10.17.202.19:19888 10.17.198.30:45453
> ESTABLISHED 63729/java
> tcp 277 0 10.17.202.19:19888 10.17.198.30:49184
> ESTABLISHED 63729/java
> tcp 1 0 10.17.202.19:19888 10.17.202.13:49992
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52703
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52707
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52708
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52710
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52714
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52723
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52726
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52727
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52739
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52749
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52753
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52757
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52760
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52820
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52827
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52829
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52831
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52833
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52836
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52839
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52841
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52843
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52850
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52860
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52876
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52879
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52881
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52884
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52886
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52888
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52891
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52893
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52896
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52898
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52899
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52902
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52909
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52910
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52912
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52923
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52925
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52927
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52930
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52937
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52939
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52945
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52947
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52969
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:52972
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:52975
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53004
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53007
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53009
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53011
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53052
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53058
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53059
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53063
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53071
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53084
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53093
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53095
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53097
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53101
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53104
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53106
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53108
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53110
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53112
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53114
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53115
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53117
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53121
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53123
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53125
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53127
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53129
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53131
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53134
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53138
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53140
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53153
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53155
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53157
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53159
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53173
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53176
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53177
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53178
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53179
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53181
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53183
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53201
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53204
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53218
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53267
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53270
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53275
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53278
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53280
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53283
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53293
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53296
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53299
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53309
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53312
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53314
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53317
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53320
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53322
> CLOSE_WAIT 63729/java
> tcp 256 0 10.17.202.19:19888 10.17.202.13:53338
> CLOSE_WAIT 63729/java
> tcp 261 0 10.17.202.19:19888 10.17.202.13:53340
> CLOSE_WAIT 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53364
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53366
> ESTABLISHED 63729/java
> tcp 260 0 10.17.202.19:19888 10.17.202.13:53367
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53380
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53382
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53386
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53390
> ESTABLISHED 63729/java
> tcp 255 0 10.17.202.19:19888 10.17.202.13:53392
> ESTABLISHED 63729/java
> tcp 1278 0 10.17.202.19:19888 10.17.202.18:45301
> CLOSE_WAIT 63729/java
> tcp 1278 0 10.17.202.19:19888 10.17.202.18:45303
> CLOSE_WAIT 63729/java
> tcp 1277 0 10.17.202.19:19888 10.17.202.18:45306
> ESTABLISHED 63729/java
> {noformat}
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