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https://issues.apache.org/jira/browse/HBASE-20152?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16391524#comment-16391524
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Mike Drob commented on HBASE-20152:
-----------------------------------
should unassign abandon instead of suspend when the target server is down? or
possibly declare itself successful, since in essence the region _is_ unassigned
from that server?
If there's a move_region scheduled while a server is down or is going down...
can we fail the move? or we can try to skip directly to the assign portion of
the move, and then have to make sure we don't try to assign the region to the
original server when it comes back
> [AMv2] DisableTableProcedure versus ServerCrashProcedure
> --------------------------------------------------------
>
> Key: HBASE-20152
> URL: https://issues.apache.org/jira/browse/HBASE-20152
> Project: HBase
> Issue Type: Bug
> Components: amv2
> Reporter: stack
> Assignee: stack
> Priority: Major
>
> Seeing a small spate of issues where disabled tables/regions are being
> assigned. Usually they happen when a DisableTableProcedure is running
> concurrent with a ServerCrashProcedure. See below. See associated
> HBASE-20131. This is umbrella issue for fixing.
> h3. Deadlock
> From HBASE-20137, 'TestRSGroups is Flakey',
> https://issues.apache.org/jira/browse/HBASE-20137?focusedCommentId=16390325&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16390325
> {code}
> * SCP is running because a server was aborted in test.
> * SCP starts AssignProcedure of region X from crashed server.
> * DisableTable Procedure runs because test has finished and we're doing
> table delete. Queues
> * UnassignProcedure for region X.
> * Disable Unassign gets Lock on region X first.
> * SCP AssignProcedure tries to get lock, waits on lock.
> * DisableTable Procedure UnassignProcedure RPC fails because server is down
> (Thats why the SCP).
> * Tries to expire the server it failed the RPC against. Fails (currently
> being SCP'd).
> * DisableTable Procedure Unassign is suspended. It is a suspend with lock on
> region X held
> * SCP can't run because lock on X is held
> * Test timesout.
> {code}
> h3. Delete of online Regions
> Saw this in nightly failure #452 for branch-2 in
> TestSplitTransactionOnCluster.org.apache.hadoop.hbase.regionserver.TestSplitTransactionOnCluster
> {code}
> * DisableTableProcedure is queued before SCP.
> * DisableTableProcedure Unassign fails because can't RPC to crashed server
> and can't expire.
> * Unassign is Stuck in suspend.
> * SCP runs and cleans up suspended Disable Unassign.
> * SCP completes which includes assign of Disable Unassign region.
> * Disable Unassign completes
> * Disable completes.
> * A scheduled Drop Table Procedure runs (its end of test).
> * Succeeds deleting regions that are actually assigned (see above where SCP
> assigned region).
> {code}
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