Details
Critical Description
This is on master snapshot as of a few weeks ago.
Haven't looked at the code much yet, but it seems rather fundamental. The procedure comes from meta replica assignment (HBASE-21624), in case it matters w.r.t. the engine initialization; however, the master is functional and other procedures run fine. I can also see lots of other open region procedures with a similar patterns that were initialized before this one and have run fine.
Currently, there are no other runnable procedures on master - a lot of succeeded procedures since then, the parent blocked on this procedure, and one unrelated RIT procedure waiting with timeout and being updated periodically.
The procedure itself is
157156 157155 RUNNABLE hadoop org.apache.hadoop.hbase.master.assignment.OpenRegionProcedure Wed Dec 19 17:20:27 PST 2018 Wed Dec 19 17:20:28 PST 2018 [ { region => { regionId => '1', tableName => { ... }, startKey => '', endKey => '', offline => 'false', split => 'false', replicaId => '1' }, targetServer => { hostName => 'server1', port => '17020', startCode => '1545266805778' } }, {} ]
This is in PST so it's been like that for ~19 hours.
The only line involving this PID in the log is
2018-12-19 17:20:27,974 INFO [PEWorker-4] procedure2.ProcedureExecutor: Initialized subprocedures=[{pid=157156, ppid=157155, state=RUNNABLE, hasLock=false; org.apache.hadoop.hbase.master.assignment.OpenRegionProcedure}]
There are no other useful logs for either this PID, parent PID, or region in question since. This PEWorker (4) is also alive and did some work since then, so it's not like the thread errored out somewhere.
All the PEWorker-s are waiting for work:
Thread 158 (PEWorker-16):
State: TIMED_WAITING
Blocked count: 1340
Waited count: 5064
Stack:
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
org.apache.hadoop.hbase.procedure2.AbstractProcedureScheduler.poll(AbstractProcedureScheduler.java:171)
org.apache.hadoop.hbase.procedure2.AbstractProcedureScheduler.poll(AbstractProcedureScheduler.java:153)
org.apache.hadoop.hbase.procedure2.ProcedureExecutor$WorkerThread.run(ProcedureExecutor.java:1949)
The main assignment procedure for this region is blocked on it:
157155 WAITING hadoop TransitRegionStateProcedure table=hbase:meta, region=534574363, ASSIGN Wed Dec 19 17:20:27 PST 2018 Wed Dec 19 17:20:27 PST 2018 [ { state => [ '1', '2', '3' ] }, { regionId => '1', tableName => { ... }, startKey => '', endKey => '', offline => 'false', split => 'false', replicaId => '1' }, { initialState => 'REGION_STATE_TRANSITION_GET_ASSIGN_CANDIDATE', lastState => 'REGION_STATE_TRANSITION_CONFIRM_OPENED', assignCandidate => { hostName => 'server1', port => '17020', startCode => '1545266805778' }, forceNewPlan => 'false' } ]
2018-12-19 17:20:27,673 INFO [PEWorker-9] procedure.MasterProcedureScheduler: Took xlock for pid=157155, state=RUNNABLE:REGION_STATE_TRANSITION_GET_ASSIGN_CANDIDATE, hasLock=false; TransitRegionStateProcedure table=hbase:meta, region=..., ASSIGN
2018-12-19 17:20:27,809 INFO [PEWorker-9] assignment.TransitRegionStateProcedure: Starting pid=157155, state=RUNNABLE:REGION_STATE_TRANSITION_GET_ASSIGN_CANDIDATE, hasLock=true; TransitRegionStateProcedure table=hbase:meta, region=..., ASSIGN; rit=OFFLINE, location=server1,17020,1545266805778; forceNewPlan=false, retain=false