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From "Romain Hardouin (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-11363) High Blocked NTR When Connecting
Date Wed, 13 Jul 2016 20:12:20 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-11363?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15375615#comment-15375615
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Romain Hardouin edited comment on CASSANDRA-11363 at 7/13/16 8:11 PM:
----------------------------------------------------------------------

I also see this behavior after upgrading to 2.1.14 (from 2.0.17). The JMX counter was at 0
before the upgrade.
I increased the native max threads to 256 but the NTR blocked were still at 0.6%.

As for now, the better change was to move memtable offheap (less GC time => less load =>
less all time blocked NTR). But I still see up to 0.3% of all time blocked...

Note: I see this behavior on two different clusters (hosted on AWS).



was (Author: rha):
I also see this behavior after upgrading to 2.1.14 (from 2.0.17). The JMX counter was at 0
before the upgrade.
I increased the native max threads to 256 but the NTR blocked were still at 0.6%.

As for now, the better change was to move memtable offheap (less GC time => less load =>
less all time blocked NTR). But I still see up to 0.3% of all time blocked...

Note: I see this behavior on two different clusters.

> High Blocked NTR When Connecting
> --------------------------------
>
>                 Key: CASSANDRA-11363
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11363
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Coordination
>            Reporter: Russell Bradberry
>            Assignee: Paulo Motta
>         Attachments: cassandra-102-cms.stack, cassandra-102-g1gc.stack
>
>
> When upgrading from 2.1.9 to 2.1.13, we are witnessing an issue where the machine load
increases to very high levels (> 120 on an 8 core machine) and native transport requests
get blocked in tpstats.
> I was able to reproduce this in both CMS and G1GC as well as on JVM 7 and 8.
> The issue does not seem to affect the nodes running 2.1.9.
> The issue seems to coincide with the number of connections OR the number of total requests
being processed at a given time (as the latter increases with the former in our system)
> Currently there is between 600 and 800 client connections on each machine and each machine
is handling roughly 2000-3000 client requests per second.
> Disabling the binary protocol fixes the issue for this node but isn't a viable option
cluster-wide.
> Here is the output from tpstats:
> {code}
> Pool Name                    Active   Pending      Completed   Blocked  All time blocked
> MutationStage                     0         8        8387821         0              
  0
> ReadStage                         0         0         355860         0              
  0
> RequestResponseStage              0         7        2532457         0              
  0
> ReadRepairStage                   0         0            150         0              
  0
> CounterMutationStage             32       104         897560         0              
  0
> MiscStage                         0         0              0         0              
  0
> HintedHandoff                     0         0             65         0              
  0
> GossipStage                       0         0           2338         0              
  0
> CacheCleanupExecutor              0         0              0         0              
  0
> InternalResponseStage             0         0              0         0              
  0
> CommitLogArchiver                 0         0              0         0              
  0
> CompactionExecutor                2       190            474         0              
  0
> ValidationExecutor                0         0              0         0              
  0
> MigrationStage                    0         0             10         0              
  0
> AntiEntropyStage                  0         0              0         0              
  0
> PendingRangeCalculator            0         0            310         0              
  0
> Sampler                           0         0              0         0              
  0
> MemtableFlushWriter               1        10             94         0              
  0
> MemtablePostFlush                 1        34            257         0              
  0
> MemtableReclaimMemory             0         0             94         0              
  0
> Native-Transport-Requests       128       156         387957        16            278451
> Message type           Dropped
> READ                         0
> RANGE_SLICE                  0
> _TRACE                       0
> MUTATION                     0
> COUNTER_MUTATION             0
> BINARY                       0
> REQUEST_RESPONSE             0
> PAGED_RANGE                  0
> READ_REPAIR                  0
> {code}
> Attached is the jstack output for both CMS and G1GC.
> Flight recordings are here:
> https://s3.amazonaws.com/simple-logs/cassandra-102-cms.jfr
> https://s3.amazonaws.com/simple-logs/cassandra-102-g1gc.jfr
> It is interesting to note that while the flight recording was taking place, the load
on the machine went back to healthy, and when the flight recording finished the load went
back to > 100.



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