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https://issues.apache.org/jira/browse/HBASE-4729?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13152088#comment-13152088
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ramkrishna.s.vasudevan commented on HBASE-4729:
-----------------------------------------------
@Ted
I think the best way to stop splitting from happening when alter table goes on.
Or stop alter table when splitting goes on.
If split gets completed the region that we are trying to unassign itself gets
changed and so
{code}
synchronized (this.regions) {
// Check if this region is currently assigned
if (!regions.containsKey(region)) {
debugLog(region, "Attempted to unassign region " +
region.getRegionNameAsString() + " but it is not " +
"currently assigned anywhere");
return;
}
{code}
unassign merely returns without proceeding. I tried to introduce a logic of
Retry in BulkReopen but because the region gets changed still unassign does not
complete successfully. Pls suggest...
> Race between online altering and splitting kills the master
> -----------------------------------------------------------
>
> Key: HBASE-4729
> URL: https://issues.apache.org/jira/browse/HBASE-4729
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.92.0
> Reporter: Jean-Daniel Cryans
> Assignee: ramkrishna.s.vasudevan
> Fix For: 0.92.0, 0.94.0
>
> Attachments: 4729.txt
>
>
> I was running an online alter while regions were splitting, and suddenly the
> master died and left my table half-altered (haven't restarted the master yet).
> What killed the master:
> {quote}
> 2011-11-02 17:06:44,428 FATAL org.apache.hadoop.hbase.master.HMaster:
> Unexpected ZK exception creating node CLOSING
> org.apache.zookeeper.KeeperException$NodeExistsException: KeeperErrorCode =
> NodeExists for /hbase/unassigned/f7e1783e65ea8d621a4bc96ad310f101
> 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:459)
> at
> org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.create(RecoverableZooKeeper.java:441)
> at
> org.apache.hadoop.hbase.zookeeper.ZKUtil.createAndWatch(ZKUtil.java:769)
> at
> org.apache.hadoop.hbase.zookeeper.ZKAssign.createNodeClosing(ZKAssign.java:568)
> at
> org.apache.hadoop.hbase.master.AssignmentManager.unassign(AssignmentManager.java:1722)
> at
> org.apache.hadoop.hbase.master.AssignmentManager.unassign(AssignmentManager.java:1661)
> at org.apache.hadoop.hbase.master.BulkReOpen$1.run(BulkReOpen.java:69)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662)
> {quote}
> A znode was created because the region server was splitting the region 4
> seconds before:
> {quote}
> 2011-11-02 17:06:40,704 INFO
> org.apache.hadoop.hbase.regionserver.SplitTransaction: Starting split of
> region TestTable,0012469153,1320253135043.f7e1783e65ea8d621a4bc96ad310f101.
> 2011-11-02 17:06:40,704 DEBUG
> org.apache.hadoop.hbase.regionserver.SplitTransaction:
> regionserver:62023-0x132f043bbde0710 Creating ephemeral node for
> f7e1783e65ea8d621a4bc96ad310f101 in SPLITTING state
> 2011-11-02 17:06:40,751 DEBUG org.apache.hadoop.hbase.zookeeper.ZKAssign:
> regionserver:62023-0x132f043bbde0710 Attempting to transition node
> f7e1783e65ea8d621a4bc96ad310f101 from RS_ZK_REGION_SPLITTING to
> RS_ZK_REGION_SPLITTING
> ...
> 2011-11-02 17:06:44,061 DEBUG org.apache.hadoop.hbase.zookeeper.ZKAssign:
> regionserver:62023-0x132f043bbde0710 Successfully transitioned node
> f7e1783e65ea8d621a4bc96ad310f101 from RS_ZK_REGION_SPLITTING to
> RS_ZK_REGION_SPLIT
> 2011-11-02 17:06:44,061 INFO
> org.apache.hadoop.hbase.regionserver.SplitTransaction: Still waiting on the
> master to process the split for f7e1783e65ea8d621a4bc96ad310f101
> {quote}
> Now that the master is dead the region server is spewing those last two lines
> like mad.
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