Hi St.Ack,
I noticed that one of the region server machines had time running one day in
future.
I corrected the date. I ran into some issues after restarting, I was getting
error with respect to .META. and stuff which I did not understand much. Also,
status command in hbase shell was displaying "3 servers, 1 dead" whereas I had
only 3 region server.
So, I cleaned the "/hbase" (to get to real problem) and restarted the hbase
nodes.
After starting all the 3 nodes of HBase, I ran the test app again and was
observing the log files of all the 3 region servers.
I noticed that when test app seemed hung, the web app's thread that was serving
the request has gone to sleep at below code. I think it stayed like that for
around 10 minutes before Tomcat probably interrupted it.
Thread-#8 - Thread t@29
java.lang.Thread.State: TIMED_WAITING
at java.lang.Thread.sleep(Native Method)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:791)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:589)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.relocateRegion(HConnectionManager.java:564)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionLocation(HConnectionManager.java:415)
at
org.apache.hadoop.hbase.client.ServerCallable.instantiateServer(ServerCallable.java:57)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1002)
at org.apache.hadoop.hbase.client.HTable.getRowOrBefore(HTable.java:514)
at
org.apache.hadoop.hbase.client.MetaScanner.metaScan(MetaScanner.java:133)
at
org.apache.hadoop.hbase.client.MetaScanner.metaScan(MetaScanner.java:95)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.prefetchRegionCache(HConnectionManager.java:648)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:702)
- locked java.lang.Object@75826e08
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:593)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.relocateRegion(HConnectionManager.java:564)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionLocation(HConnectionManager.java:415)
at
org.apache.hadoop.hbase.client.ServerCallable.instantiateServer(ServerCallable.java:57)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1002)
at org.apache.hadoop.hbase.client.HTable.get(HTable.java:546)
<.. app specific trace removed ...>
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
============================================================================================
After 10 minutes, web app log showed:
2011-07-10 16:50:28,804 [Thread-#8] ERROR [persistence.handler.HBaseHandler] -
Exception occurred in searchData:
java.io.IOException: Giving up trying to get region server: thread is
interrupted.
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1016)
at org.apache.hadoop.hbase.client.HTable.get(HTable.java:546)
============================================================================================
I did not see anything happening on region server either, the log had
occasional entries like these:
2011-07-10 16:43:53,648 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache:
LRU Stats: total=6.52 MB, free=788.08 MB, max=794.6 MB, blocks=0,
accesses=1080, hits=0, hitRatio=0.00%%, cachingAccesses=0, cachingHits=0,
cachingHitsRatio=�%, evictions=0, evicted=0, evictedPerRun=NaN
2011-07-10 16:48:53,649 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache:
LRU Stats: total=6.52 MB, free=788.08 MB, max=794.6 MB, blocks=0,
accesses=1080, hits=0, hitRatio=0.00%%, cachingAccesses=0, cachingHits=0,
cachingHitsRatio=�%, evictions=0, evicted=0, evictedPerRun=NaN
2011-07-10 16:53:53,648 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache:
LRU Stats: total=6.52 MB, free=788.08 MB, max=794.6 MB, blocks=0,
accesses=1080, hits=0, hitRatio=0.00%%, cachingAccesses=0, cachingHits=0,
cachingHitsRatio=�%, evictions=0, evicted=0, evictedPerRun=NaN
2
Regards,
Srikanth
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Stack
Sent: Saturday, July 09, 2011 9:41 PM
To: [email protected]
Subject: Re: HBase Read and Write Issues in Mutlithreaded Environments
You read the requirements section in our docs and you have upped the
ulimits, nprocs, etc? http://hbase.apache.org/book/os.html
If you know the row, can you deduce the regionserver its talking too?
(Below is the client failure -- we need to figure whats up on
server-side). Once you've done that, can you check its logs? See if
you can figure anything on why the hang?
Thanks,
St.Ack
On Sat, Jul 9, 2011 at 6:14 AM, Srikanth P. Shreenivas
<[email protected]> wrote:
> Hi St.Ack,
>
> We upgraded to CDH 3 (hadoop-0.20-0.20.2+923.21-1.noarch.rpm,
> hadoop-hbase-0.90.1+15.18-1.noarch.rpm,
> hadoop-zookeeper-3.3.3+12.1-1.noarch.rpm).
>
> I ran a the same test which I was running for the app when it was running on
> CDH2. The test app posts a request the web app every 100ms, and the web app
> reads a HBase record, performs some logic, and saves an audit trail by
> writing another HBase record.
>
> When our app was running on CDH2, I observed the below issue for every 10 to
> 15 requests.
> With CDH3, this issue is not happening at all. So, seems like situation has
> improved a lot, and our app seems to be lot more stable.
>
> However, I am still seeing an issue though. There are many requests (around
> 1%) which are not able to read the record from the HBase, and the get call is
> hanging for almost 10 minutes. This is what I see in application log:
>
> 2011-07-09 18:27:25,537 [gridgain-#6%authGrid%] ERROR [my.app.HBaseHandler]
> - Exception occurred in searchData:
> java.io.IOException: Giving up trying to get region server: thread is
> interrupted.
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1016)
> at org.apache.hadoop.hbase.client.HTable.get(HTable.java:546)
>
> <...app specific trace removed...>
>
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
> at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
> at java.util.concurrent.FutureTask.run(FutureTask.java:138)
> at
> org.gridgain.grid.util.runnable.GridRunnable.run(GridRunnable.java:194)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:619)
>
>
> I am running the test on the same record, so all by "get" are for same row id.
>
>
>
> It will be of immense help if you can provide some inputs on whether we are
> missing some configuration settings, or is there a way to get around this.
>
> Thanks,
> Srikanth
>
>
>
>
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Stack
> Sent: Wednesday, June 29, 2011 7:48 PM
> To: [email protected]
> Subject: Re: HBase Read and Write Issues in Mutlithreaded Environments
>
> Go to CDH3 if you can. CDH2 is also old.
> St.Ack
>
> On Wed, Jun 29, 2011 at 7:15 AM, Srikanth P. Shreenivas
> <[email protected]> wrote:
>> Thanks St. Ack for the inputs.
>>
>> Will upgrading to CDH3 help or is there a version within CDH2 that you
>> recommend we should upgrade to?
>>
>> Regards,
>> Srikanth
>>
>> -----Original Message-----
>> From: [email protected] [mailto:[email protected]] On Behalf Of Stack
>> Sent: Wednesday, June 29, 2011 11:16 AM
>> To: [email protected]
>> Subject: Re: HBase Read and Write Issues in Mutlithreaded Environments
>>
>> Can you upgrade? That release is > 18 months old. A bunch has
>> happened in the meantime.
>>
>> For retries exhausted, check whats going on on the remote regionserver
>> that you are trying to write too. Its probably struggling and thats
>> why requests are not going through -- or the client missed the fact
>> that region moved (all stuff that should be working better in latest
>> hbase).
>>
>> St.Ack
>>
>> On Tue, Jun 28, 2011 at 9:51 PM, Srikanth P. Shreenivas
>> <[email protected]> wrote:
>>> Hi,
>>>
>>> We are using HBase 0.20.3 (hbase-0.20-0.20.3-1.cloudera.noarch.rpm) cluster
>>> in distributed mode with Hadoop 0.20.2 (hadoop-0.20-0.20.2+320-1.noarch).
>>> We are using pretty much default configuration, and only thing we have
>>> customized is that we have allocated 4GB RAM in
>>> /etc/hbase-0.20/conf/hbase-env.sh
>>>
>>> In our setup, we have a web application that reads a record from HBase and
>>> writes a record as part of each web request. The application is hosted in
>>> Apache Tomcat 7 and is a stateless web application providing a REST-like
>>> web service API.
>>>
>>> We are observing that our reads and writes times out once in a while.
>>> This happens more for writes.
>>> We see below exception in our application logs:
>>>
>>>
>>> Exception Type 1 - During Get:
>>> ---------------------------------------
>>> org.apache.hadoop.hbase.client.RetriesExhaustedException: Trying to contact
>>> region server 10.1.68.36:60020 for region
>>> employeedata,be8784ac8b57c45625a03d52be981b88097c2fdc,1308657957879, row
>>> 'd51b74eb05e07f96cee0ec556f5d8d161e3281f3', but failed after 10 attempts.
>>> Exceptions:
>>> java.io.IOException: Call to /10.1.68.36:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>> java.nio.channels.ClosedByInterruptException
>>>
>>> at
>>> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.getRegionServerWithRetries(HConnectionManager.java:1048)
>>> at org.apache.hadoop.hbase.client.HTable.get(HTable.java:417)
>>> <snip>
>>>
>>> Exception Type 2 - During Put:
>>> ---------------------------------------------
>>> Caused by: org.apache.hadoop.hbase.client.RetriesExhaustedException: Trying
>>> to contact region server 10.1.68.34:60020 for region
>>> audittable,,1309183872019, row '2a012017120f80a801b28f5f66a83dc2a8882d1b',
>>> but failed after 10 attempts.
>>> Exceptions:
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>> java.io.IOException: Call to /10.1.68.34:60020 failed on local exception:
>>> java.nio.channels.ClosedByInterruptException
>>>
>>> at
>>> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.getRegionServerWithRetries(HConnectionManager.java:1048)
>>> at
>>> org.apache.hadoop.hbase.client.HConnectionManager$TableServers$3.doCall(HConnectionManager.java:1239)
>>> at
>>> org.apache.hadoop.hbase.client.HConnectionManager$TableServers$Batch.process(HConnectionManager.java:1161)
>>> at
>>> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.processBatchOfRows(HConnectionManager.java:1247)
>>> at
>>> org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:609)
>>> at org.apache.hadoop.hbase.client.HTable.put(HTable.java:474)
>>> <snip>
>>>
>>> Any inputs on why this is happening, or how to rectify it will be of
>>> immense help.
>>>
>>> Thanks,
>>> Srikanth
>>>
>>>
>>>
>>> Srikanth P Shreenivas|Principal Consultant | MindTree Ltd.|Global Village,
>>> RVCE Post, Mysore Road, Bangalore-560 059, INDIA|Voice +91 80 26264000 /
>>> Fax +91 80 2626 4100| Mob: 9880141059|email:
>>> [email protected]<mailto:[email protected]>
>>> |www.mindtree.com<http://www.mindtree.com/> |
>>>
>>>
>>> ________________________________
>>>
>>> http://www.mindtree.com/email/disclaimer.html
>>>
>>
>
