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https://issues.apache.org/jira/browse/HBASE-21614?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16750770#comment-16750770
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Duo Zhang commented on HBASE-21614:
-----------------------------------
branch-2.0/2.1 should be safe, the initialization part was refactored on
branch-2 and above and introduced this problem, I suppose.
> RIT recovery with ServerCrashProcedure doesn't account for all regions
> ----------------------------------------------------------------------
>
> Key: HBASE-21614
> URL: https://issues.apache.org/jira/browse/HBASE-21614
> Project: HBase
> Issue Type: Bug
> Components: amv2
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Priority: Critical
> Fix For: 3.0.0, 2.2.0
>
> Attachments: HBASE-21614-v1.patch, HBASE-21614.01.patch,
> HBASE-21614.patch, HBASE-21614.patch
>
>
> Master is restarting after a previous master crashed while recovering some
> regions from a dead server.
> Master recovers RIT for the region, however the RIT has no location (logged,
> at least) in CONFIRM_CLOSE state. That is a potential problem #0.5 - confirm
> where? But that should be covered by meta, so not a big deal, right. As such
> it doesn't seem to add the region to server map anywhere
> {noformat}
> 2018-12-17 14:51:14,606 INFO [master/:17000:becomeActiveMaster]
> assignment.AssignmentManager: Attach pid=38015,
> state=RUNNABLE:REGION_STATE_TRANSITION_CONFIRM_CLOSED, hasLock=false;
> TransitRegionStateProcedure table=t1, region=region1, REOPEN/MOVE to
> rit=OFFLINE, location=null, table=t1, region=region1 to restore RIT
> {noformat}
> -However, in this case ServerCrashProcedure for the server kicks off BEFORE
> meta is loaded-.
> -That seems to be a problem #1 - it immediately gets regions to later
> recover, so in this case it gets nothing-.
> -I've grepped our logs for successful cases of SCP interacting with region
> transition at startup, and in all cases the meta was loaded before SCP-.
> -Seems like a race condition-. Looks like SCP handles it
> {noformat}
> 2018-12-17 14:51:14,625 INFO [master/:17000:becomeActiveMaster]
> master.RegionServerTracker: Starting RegionServerTracker; 0 have existing
> ServerCrashProcedures, 103 possibly 'live' servers, and 1 'splitting'.
> 2018-12-17 14:51:20,770 INFO [master/:17000:becomeActiveMaster]
> master.ServerManager: Processing expiration of server1,17020,1544636616174 on
> ,17000,1545087053243
> 2018-12-17 14:51:20,921 INFO [master/:17000:becomeActiveMaster]
> assignment.AssignmentManager: Added server1,17020,1544636616174 to dead
> servers which carryingMeta=false, submitted ServerCrashProcedure pid=111298
> 2018-12-17 14:51:30,728 INFO [PEWorker-13] procedure.ServerCrashProcedure:
> Start pid=111298, state=RUNNABLE:SERVER_CRASH_START, hasLock=true;
> ServerCrashProcedure server=server1,17020,1544636616174, splitWal=true,
> meta=false
> {noformat}
> Meta is only loaded 11-12 seconds later.
> If one looks at meta-loading code however, there is one more problem #2 - the
> region is in CLOSING state, so the {{addRegionToServer}} is not going to be
> called - it's only called for OPENED regions.
> Expanding on the above, I've only seen SCP unblock stuck region transition at
> startup when region started out in meta as OPEN.
> {noformat}
> 2018-12-17 14:51:42,403 INFO [master/:17000:becomeActiveMaster]
> assignment.RegionStateStore: Load hbase:meta entry region=region1,
> regionState=CLOSING, lastHost=server1,17020,1544636616174,
> regionLocation=server1,17020,1544636616174, openSeqNum=629131
> {noformat}
> SCP predictably finishes without doing anything; no other logs for this pid
> {noformat}
> 2018-12-17 14:52:19,046 INFO [PEWorker-2] procedure2.ProcedureExecutor:
> Finished pid=111298, state=SUCCESS, hasLock=false; ServerCrashProcedure
> server=server1,17020,1544636616174, splitWal=true, meta=false in 58.0010sec
> {noformat}
> After that, region is still stuck trying to be closed in
> TransitRegionStateProcedure; it's in the same state for hours including
> across master restarts.
> {noformat}
> 2018-12-17 15:09:35,216 WARN [PEWorker-14]
> assignment.TransitRegionStateProcedure: Failed transition, suspend 604secs
> pid=38015, state=RUNNABLE:REGION_STATE_TRANSITION_CLOSE, hasLock=true;
> TransitRegionStateProcedure table=t1, region=region1, REOPEN/MOVE;
> rit=CLOSING, location=server1,17020,1544636616174; waiting on rectified
> condition fixed by other Procedure or operator intervention
> {noformat}
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