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https://issues.apache.org/jira/browse/HBASE-20796?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16526995#comment-16526995
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Duo Zhang commented on HBASE-20796:
-----------------------------------
{quote}
Would Dispatch then need to know about Procedures? They've been intentionally
done as distinct systems up to this.
{quote}
I mean add something in the Assign/Unassign procedures to prevent redundant
call. For example, for unassign, it is a one time deal, we just need to add a
simple flag, if it is finished by a SCP then no one call finish it again. And
for assign, maybe we could introduce something like an epoch, it will be
increased if we restart from the beginning to assign the region again. If a
remoteCallXXX is coming, we first need to check if the epoch matches, if not,
just ignore it.
> STUCK RIT though region successfully assigned
> ---------------------------------------------
>
> Key: HBASE-20796
> URL: https://issues.apache.org/jira/browse/HBASE-20796
> Project: HBase
> Issue Type: Bug
> Components: amv2
> Reporter: stack
> Assignee: stack
> Priority: Major
> Fix For: 3.0.0, 2.1.0, 2.0.2
>
> Attachments: HBASE-20796.branch-2.0.001.patch
>
>
> This is a good one. We keep logging messages like this:
> {code}
> 2018-06-26 12:32:24,859 WARN
> org.apache.hadoop.hbase.master.assignment.AssignmentManager: STUCK
> Region-In-Transition rit=OPENING,
> location=vd0410.X.Y.com,22101,1529611445046,
> table=IntegrationTestBigLinkedList_20180525080406,
> region=e10b35d49528e2453a04c7038e3393d7
> {code}
> ...though the region is successfully assigned.
> Story:
> * Dispatch an assign 2018-06-26 12:31:27,390 INFO
> org.apache.hadoop.hbase.master.assignment.RegionTransitionProcedure: Dispatch
> pid=370829, ppid=370391, state=RUNNABLE:REGION_TRANSITION_DISPATCH;
> AssignProcedure table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2; rit=OPENING,
> location=vd0410.X.Y.Z,22101,1529611445046
> * It gets stuck 2018-06-26 12:32:29,860 WARN
> org.apache.hadoop.hbase.master.assignment.AssignmentManager: STUCK
> Region-In-Transition rit=OPENING, location=vd0410.X.Y.Z,22101,1529611445046,
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2 (Because the server was killed)
> * We stay STUCK for a while.
> * The Master notices the server as crashed and starts a SCP.
> * SCP kills ongoing assign: 2018-06-26 12:32:54,809 INFO
> org.apache.hadoop.hbase.master.procedure.ServerCrashProcedure: pid=371105
> found RIT pid=370829, ppid=370391, state=RUNNABLE:REGION_TRANSITION_DISPATCH;
> AssignProcedure table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2; rit=OPENING,
> location=vd0410.X.Y.Z,22101,1529611445046
> * The kill brings on a retry ... 2018-06-26 12:32:54,810 WARN
> org.apache.hadoop.hbase.master.assignment.RegionTransitionProcedure: Remote
> call failed pid=370829, ppid=370391,
> state=RUNNABLE:REGION_TRANSITION_DISPATCH; AssignProcedure
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2; rit=OPENING,
> location=vd0410.X.Y.Z,22101,1529611445046; exception=ServerCrashProcedure
> pid=371105, server=vd0410.X.Y.Z,22101,1529611445046
> * Which eventually succeeds..... Successfully deployed to new server
> 2018-06-26 12:32:55,429 INFO
> org.apache.hadoop.hbase.procedure2.ProcedureExecutor: Finished pid=370829,
> ppid=370391, state=SUCCESS; AssignProcedure
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2 in 1mins, 35.379sec
> * But then, it looks like the RPC was ongoing and it broke in following way
> 2018-06-26 12:33:06,378 WARN
> org.apache.hadoop.hbase.master.assignment.RegionTransitionProcedure: Remote
> call failed pid=370829, ppid=370391, state=SUCCESS; AssignProcedure
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2; rit=OPEN,
> location=vc0614.halxg.cloudera.com,22101,1529611443424; exception=Call to
> vd0410.X.Y.Z/10.10.10.10:22101 failed on local exception:
> org.apache.hbase.thirdparty.io.netty.channel.unix.Errors$NativeIoException:
> syscall:read(..) failed: Connection reset by peer (Notice how state for
> region is OPEN and 'SUCCESS').
> * Then says 2018-06-26 12:33:06,380 INFO
> org.apache.hadoop.hbase.master.assignment.AssignProcedure: Retry=1 of max=10;
> pid=370829, ppid=370391, state=SUCCESS; AssignProcedure
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2; rit=OPEN,
> location=vc0614.X.Y.Z,22101,1529611443424
> * And finally... 2018-06-26 12:34:10,727 WARN
> org.apache.hadoop.hbase.master.assignment.AssignmentManager: STUCK
> Region-In-Transition rit=OFFLINE, location=null,
> table=IntegrationTestBigLinkedList_20180612114844,
> region=f69ccf7d9178ce166b515e0e2ef019d2
> Restart of Master got rid of the STUCK complaints.
> This is interesting because the stuck rpc and the successful reassign are all
> riding on the same pid.
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