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https://issues.apache.org/jira/browse/HBASE-6299?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13406838#comment-13406838
]
ramkrishna.s.vasudevan commented on HBASE-6299:
-----------------------------------------------
@Maryann/Stack
I can tell one scenario where this patch will lead to inconsistency.
In the patch
{code}
else {
+ // The destination region server is probably processing the region
open, so it
+ // might be safer to try this region server again to avoid having
two region
+ // servers open the same region.
+ LOG.warn("Call openRegion() to " + plan.getDestination() +
+ " has timed out when trying to assign " +
region.getRegionNameAsString() +
+ ". Trying to assign to this region server again; retry=" + i,
t);
+ state.update(RegionState.State.OFFLINE);
+ continue;
+ }
{code}
Now because the RS is already opening i tend to assign it to same RS and i
update the inmemory state to OFFLINE. At that time the RS has moved the znode
from OFFLINE to OPENING or OPENINIG to OPENED. Now there is a check in
handleRegion
{code}
if (regionState == null ||
(!regionState.isPendingOpen() && !regionState.isOpening())) {
LOG.warn("Received OPENING for region " +
prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not " +
"in expected PENDING_OPEN or OPENING states");
return;
}
{code}
So the master skips the transition. Now any way as we are trying out the
assignment to same RS, we will either get RegionAlreadyInTransistion or
sometimes even ALREADY_OPENED.
If i get ALREADY_OPENED we are handling it correctly by adding to this.regions.
But if i get RegionAlreadyInTransistion we just skip the assign next time.
Now in the RS side the region could have been made online by this time but the
master is not aware of this.
One more thing is
{code}
+ else if (t instanceof java.net.SocketTimeoutException) {
+ if (this.regionsInTransition.get(region.getEncodedName()) == null
+ &&
plan.getDestination().equals(getRegionServerOfRegion(region))) {
{code}
Here the plan could be cleared on regionOnline if RIT is cleared?
Ideally over in HBASE-6060 we were trying to see how good is the retry option
in assign. Sometimes the retry option and SSH were causing double assignments
which we were trying to solve.
Here, Can we have an option to shutdown the RS incase of sockettimeout by the
master so that atleast we are sure that the SSH will take care of ssignment?
> RS starts region open while fails ack to HMaster.sendRegionOpen() causes
> inconsistency in HMaster's region state and a series of successive problems.
> -----------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-6299
> URL: https://issues.apache.org/jira/browse/HBASE-6299
> Project: HBase
> Issue Type: Bug
> Components: master
> Affects Versions: 0.90.6, 0.94.0
> Reporter: Maryann Xue
> Assignee: Maryann Xue
> Priority: Critical
> Attachments: HBASE-6299-v2.patch, HBASE-6299.patch
>
>
> 1. HMaster tries to assign a region to an RS.
> 2. HMaster creates a RegionState for this region and puts it into
> regionsInTransition.
> 3. In the first assign attempt, HMaster calls RS.openRegion(). The RS
> receives the open region request and starts to proceed, with success
> eventually. However, due to network problems, HMaster fails to receive the
> response for the openRegion() call, and the call times out.
> 4. HMaster attemps to assign for a second time, choosing another RS.
> 5. But since the HMaster's OpenedRegionHandler has been triggered by the
> region open of the previous RS, and the RegionState has already been removed
> from regionsInTransition, HMaster finds invalid and ignores the unassigned ZK
> node "RS_ZK_REGION_OPENING" updated by the second attempt.
> 6. The unassigned ZK node stays and a later unassign fails coz
> RS_ZK_REGION_CLOSING cannot be created.
> {code}
> 2012-06-29 07:03:38,870 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Using pre-existing plan for
> region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.;
>
> plan=hri=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.,
> src=swbss-hadoop-004,60020,1340890123243,
> dest=swbss-hadoop-006,60020,1340890678078
> 2012-06-29 07:03:38,870 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Assigning region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> to swbss-hadoop-006,60020,1340890678078
> 2012-06-29 07:03:38,870 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=M_ZK_REGION_OFFLINE, server=swbss-hadoop-002:60000,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:06:28,882 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-006,60020,1340890678078,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:06:32,291 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-006,60020,1340890678078,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:06:32,299 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENED, server=swbss-hadoop-006,60020,1340890678078,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:06:32,299 DEBUG
> org.apache.hadoop.hbase.master.handler.OpenedRegionHandler: Handling OPENED
> event for
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> from serverName=swbss-hadoop-006,60020,1340890678078, load=(requests=518945,
> regions=575, usedHeap=15282, maxHeap=31301); deleting unassigned node
> 2012-06-29 07:06:32,299 DEBUG org.apache.hadoop.hbase.zookeeper.ZKAssign:
> master:60000-0x2377fee2ae80007 Deleting existing unassigned node for
> b713fd655fa02395496c5a6e39ddf568 that is in expected state RS_ZK_REGION_OPENED
> 2012-06-29 07:06:32,301 DEBUG org.apache.hadoop.hbase.zookeeper.ZKAssign:
> master:60000-0x2377fee2ae80007 Successfully deleted unassigned node for
> region b713fd655fa02395496c5a6e39ddf568 in expected state RS_ZK_REGION_OPENED
> 2012-06-29 07:06:32,301 DEBUG
> org.apache.hadoop.hbase.master.handler.OpenedRegionHandler: The master has
> opened the region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> that was online on serverName=swbss-hadoop-006,60020,1340890678078,
> load=(requests=518945, regions=575, usedHeap=15282, maxHeap=31301)
> 2012-06-29 07:07:41,140 WARN
> org.apache.hadoop.hbase.master.AssignmentManager: Failed assignment of
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> to serverName=swbss-hadoop-006,60020,1340890678078, load=(requests=0,
> regions=575, usedHeap=0, maxHeap=0), trying to assign elsewhere instead;
> retry=0
> java.net.SocketTimeoutException: Call to /172.16.0.6:60020 failed on socket
> timeout exception: java.net.SocketTimeoutException: 120000 millis timeout
> while waiting for channel to be ready for read. ch :
> java.nio.channels.SocketChannel[connected local=/172.16.0.2:53765
> remote=/172.16.0.6:60020]
> at
> org.apache.hadoop.hbase.ipc.HBaseClient.wrapException(HBaseClient.java:805)
> at org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:778)
> at
> org.apache.hadoop.hbase.ipc.HBaseRPC$Invoker.invoke(HBaseRPC.java:283)
> at $Proxy8.openRegion(Unknown Source)
> at
> org.apache.hadoop.hbase.master.ServerManager.sendRegionOpen(ServerManager.java:573)
> at
> org.apache.hadoop.hbase.master.AssignmentManager.assign(AssignmentManager.java:1127)
> at
> org.apache.hadoop.hbase.master.AssignmentManager.assign(AssignmentManager.java:912)
> at
> org.apache.hadoop.hbase.master.AssignmentManager.assign(AssignmentManager.java:892)
> at
> org.apache.hadoop.hbase.master.handler.ClosedRegionHandler.process(ClosedRegionHandler.java:92)
> at
> org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:162)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662)
> Caused by: java.net.SocketTimeoutException: 120000 millis timeout while
> waiting for channel to be ready for read. ch :
> java.nio.channels.SocketChannel[connected local=/172.16.0.2:53765
> remote=/172.16.0.6:60020]
> at
> org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:164)
> at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:155)
> at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:128)
> at java.io.FilterInputStream.read(FilterInputStream.java:116)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection$PingInputStream.read(HBaseClient.java:301)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
> at java.io.DataInputStream.readInt(DataInputStream.java:370)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.receiveResponse(HBaseClient.java:541)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.run(HBaseClient.java:479)
> 2012-06-29 07:07:41,142 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: No previous transition plan
> was found (or we are ignoring an existing plan) for
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> so generated a random one;
> hri=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.,
> src=, dest=swbss-hadoop-164,60020,1340888346294; 15 (online=15,
> exclude=serverName=swbss-hadoop-006,60020,1340890678078, load=(requests=0,
> regions=575, usedHeap=0, maxHeap=0)) available servers
> 2012-06-29 07:07:41,142 DEBUG org.apache.hadoop.hbase.zookeeper.ZKAssign:
> master:60000-0x2377fee2ae80007 Creating (or updating) unassigned node for
> b713fd655fa02395496c5a6e39ddf568 with OFFLINE state
> 2012-06-29 07:07:41,145 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Using pre-existing plan for
> region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.;
>
> plan=hri=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.,
> src=, dest=swbss-hadoop-164,60020,1340888346294
> 2012-06-29 07:07:41,145 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Assigning region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> to swbss-hadoop-164,60020,1340888346294
> 2012-06-29 07:07:41,149 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-164,60020,1340888346294,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:07:41,150 WARN
> org.apache.hadoop.hbase.master.AssignmentManager: Received OPENING for region
> b713fd655fa02395496c5a6e39ddf568 from server
> swbss-hadoop-164,60020,1340888346294 but region was in the state null and
> not in expected PENDING_OPEN or OPENING states
> 2012-06-29 07:07:41,296 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-164,60020,1340888346294,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:07:41,296 WARN
> org.apache.hadoop.hbase.master.AssignmentManager: Received OPENING for region
> b713fd655fa02395496c5a6e39ddf568 from server
> swbss-hadoop-164,60020,1340888346294 but region was in the state null and
> not in expected PENDING_OPEN or OPENING states
> 2012-06-29 07:07:41,302 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Handling
> transition=RS_ZK_REGION_OPENED, server=swbss-hadoop-164,60020,1340888346294,
> region=b713fd655fa02395496c5a6e39ddf568
> 2012-06-29 07:07:41,302 WARN
> org.apache.hadoop.hbase.master.AssignmentManager: Received OPENED for region
> b713fd655fa02395496c5a6e39ddf568 from server
> swbss-hadoop-164,60020,1340888346294 but region was in the state null and
> not in expected PENDING_OPEN or OPENING states
> 2012-06-29 07:08:38,872 INFO org.apache.hadoop.hbase.master.HMaster: balance
> hri=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.,
> src=swbss-hadoop-006,60020,1340890678078,
> dest=swbss-hadoop-008,60020,1340891085175
> 2012-06-29 07:08:38,872 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Starting unassignment of
> region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> (offlining)
> 2012-06-29 07:08:47,875 DEBUG
> org.apache.hadoop.hbase.master.AssignmentManager: Sent CLOSE to
> serverName=swbss-hadoop-006,60020,1340890678078, load=(requests=0, regions=0,
> usedHeap=0, maxHeap=0) for region
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> ...
> 2012-06-29 08:04:37,681 INFO
> org.apache.hadoop.hbase.master.AssignmentManager: Regions in transition timed
> out:
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> state=PENDING_CLOSE, ts=1340926468331, server=null
> 2012-06-29 08:04:37,681 INFO
> org.apache.hadoop.hbase.master.AssignmentManager: Region has been
> PENDING_CLOSE for too long, running forced unassign again on
> region=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> 2012-06-29 08:04:47,681 INFO
> org.apache.hadoop.hbase.master.AssignmentManager: Regions in transition timed
> out:
> CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> state=PENDING_CLOSE, ts=1340926468331, server=null
> 2012-06-29 08:04:47,682 INFO
> org.apache.hadoop.hbase.master.AssignmentManager: Region has been
> PENDING_CLOSE for too long, running forced unassign again on
> region=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
> {code}
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