zookeeper.KeeperException$NodeExistsException if HMaster restarts while table
is being disabled
-----------------------------------------------------------------------------------------------
Key: HBASE-4265
URL: https://issues.apache.org/jira/browse/HBASE-4265
Project: HBase
Issue Type: Bug
Reporter: Ming Ma
Assignee: Ming Ma
There seems to be more than just one issue regarding the following scenario. I
would provide a fix later just for this exception.
1. A table is being disabled.
2. HMaster restarted.
3. At HMaster startup, it tries to transition from disabling to disabled state.
It got the following exception.
org.apache.zookeeper.KeeperException$NodeExistsException: KeeperErrorCode =
NodeExists for /hbase/unassigned/419b902243c836c285108ba555b712fa
at org.apache.zookeeper.KeeperException.create(KeeperException.java:110)
at org.apache.zookeeper.KeeperException.create(KeeperException.java:42)
at org.apache.zookeeper.ZooKeeper.create(ZooKeeper.java:637)
at
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.createNonSequential(RecoverableZooKeeper.java:475)
at
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.create(RecoverableZooKeeper.java:457)
at
org.apache.hadoop.hbase.zookeeper.ZKUtil.createAndWatch(ZKUtil.java:742)
at
org.apache.hadoop.hbase.zookeeper.ZKAssign.createNodeClosing(ZKAssign.java:461)
at
org.apache.hadoop.hbase.master.AssignmentManager.unassign(AssignmentManager.java:1440)
at
org.apache.hadoop.hbase.master.AssignmentManager.unassign(AssignmentManager.java:1406)
at
org.apache.hadoop.hbase.master.handler.DisableTableHandler$BulkDisabler$1.run(DisableTableHandler.java:141)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
This issue is this specific region is in a special state before HMaster
restarts; it has been closed by RS properly thus the zk state is
RS_ZK_REGION_CLOSED. However, HMaster hasn't got a chance to process
ClosedRegionHandler yet and thus the node remains at zk. After RS restarts,
this node is added to online region list first in
AssignmentManager.rebuildUserRegions and tries to unassign it later.
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