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https://issues.apache.org/jira/browse/HBASE-16270?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15400525#comment-15400525
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Robert Yokota commented on HBASE-16270:
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It appears that this.snapshotId is set to -1 at the end of clearSnapshot(). So
one way I could see the above error happening is if two threads are
concurrently calling HStore.updateStoreFiles. In HStore.updateStoreFiles there
is write lock that is obtained. The second thread will wait for the lock, and
when it obtains the lock it will call clearSnapshot() after the first thread
has already called it. Since the snapshot has already been cleared
(this.snapshotId set to -1), the second call to clearSnapshot should just
return, instead of throwing UnexpectedStateException.
> When using region replicas, get thousands of occurrences of
> UnexpectedStateException: Current snapshot id is -1
> ---------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-16270
> URL: https://issues.apache.org/jira/browse/HBASE-16270
> Project: HBase
> Issue Type: Bug
> Components: Replication
> Affects Versions: 1.1.2
> Reporter: Robert Yokota
> Attachments: HBASE-16270-branch-1.2.patch, HBASE-16270-master.patch
>
>
> We have an HBase (1.1.2) production cluster with 58 region servers and a
> staging cluster with 6 region servers.
> For both clusters, we enabled region replicas with the following settings:
> hbase.regionserver.storefile.refresh.period = 0
> hbase.region.replica.replication.enabled = true
> hbase.region.replica.replication.memstore.enabled = true
> hbase.master.hfilecleaner.ttl = 3600000
> hbase.master.loadbalancer.class =
> org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer
> hbase.meta.replica.count = 3
> hbase.regionserver.meta.storefile.refresh.period = 30000
> hbase.region.replica.wait.for.primary.flush = true
> hbase.region.replica.storefile.refresh.memstore.multiplier = 4
> We then altered our HBase tables to have REGION_REPLICATION => 2
> Both clusters got into a state where a few region servers were spewing the
> following error below in the HBase logs. In one instance the error occurred
> over 70K times. At this time, these region servers would see 10x write
> traffic (the hadoop.HBase.RegionServer.Server.writeRequestCount metric) and
> in some instances would crash.
> At the same time, we would see secondary regions move and then go into the
> "reads are disabled" state for extended periods.
> It appears there is a race condition where the DefaultMemStore::clearSnapshot
> method might be called more than once in succession. The first call would set
> snapshotId to -1, but the second call would throw an exception. It seems the
> second call should just return if the snapshotId is already -1, rather than
> throwing an exception.
> Thu Jul 21 08:38:50 UTC 2016,
> RpcRetryingCaller{globalStartTime=1469090201543, pause=100, retries=35},
> org.apache.hadoop.hbase.regionserver.UnexpectedStateException:
> org.apache.hadoop.hbase.regionserver.UnexpectedStateException: Current
> snapshot id is -1,passed 1469085004304
> at
> org.apache.hadoop.hbase.regionserver.DefaultMemStore.clearSnapshot(DefaultMemStore.java:187)
> at
> org.apache.hadoop.hbase.regionserver.HStore.updateStorefiles(HStore.java:1054)
> at
> org.apache.hadoop.hbase.regionserver.HStore.access$500(HStore.java:128)
> at
> org.apache.hadoop.hbase.regionserver.HStore$StoreFlusherImpl.replayFlush(HStore.java:2270)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.replayFlushInStores(HRegion.java:4487)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.replayWALFlushCommitMarker(HRegion.java:4388)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.replayWALFlushMarker(HRegion.java:4191)
> at
> org.apache.hadoop.hbase.regionserver.RSRpcServices.doReplayBatchOp(RSRpcServices.java:776)
> at
> org.apache.hadoop.hbase.regionserver.RSRpcServices.replay(RSRpcServices.java:1655)
> at
> org.apache.hadoop.hbase.protobuf.generated.AdminProtos$AdminService$2.callBlockingMethod(AdminProtos.java:22255)
> at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2114)
> at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:101)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130)
> at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107)
> at java.lang.Thread.run(Thread.java:745)
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