| [CDO] Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893639] |
Thu, 05 July 2012 04:13  |
 Apirom Na Nakorn
Messages: 14
Registered: July 2012 |
Junior Member |
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Hi,
I try to commit data(65535 elements for each client and the size of each element is 1KB) from 4 clients simultaneously to 4 resource path under the same repository in CDO Server (4.1), but I get IOTimeoutException so I set the new timout in session.options().getNet4jProtocol().setTimeout() to ISignalProtocol.NO_TIMEOUT and run again. This time I get an exception as follow :
Caused by: org.eclipse.emf.cdo.util.CommitException: Rollback in DBStore: java.lang.OutOfMemoryError: GC overhead limit exceeded
at java.lang.StringCoding$StringDecoder.decode(Unknown Source)
at java.lang.StringCoding.decode(Unknown Source)
at java.lang.String.<init>(Unknown Source)
at java.lang.String.<init>(Unknown Source)
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:754)
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:707)
at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:4718)
at org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.ObjectTypeTable.putObjectType(ObjectTypeTable.java:116)
at org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.DelegatingObjectTypeMapper.putObjectType(DelegatingObjectTypeMapper.java:68)
at org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.AbstractHorizontalMappingStrategy.putObjectType(AbstractHorizontalMappingStrategy.java:81)
at org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.HorizontalBranchingClassMapping.writeRevision(HorizontalBranchingClassMapping.java:763)
at org.eclipse.emf.cdo.server.internal.db.DBStoreAccessor.writeRevision(DBStoreAccessor.java:583)
at org.eclipse.emf.cdo.server.internal.db.DBStoreAccessor.writeRevisions(DBStoreAccessor.java:563)
at org.eclipse.emf.cdo.spi.server.StoreAccessor.doWrite(StoreAccessor.java:94)
at org.eclipse.emf.cdo.spi.server.StoreAccessorBase.write(StoreAccessorBase.java:149)
How to solve this problem ?
Thanks in advance
Neung
[Updated on: Thu, 05 July 2012 04:17] Report message to a moderator |
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| Re: CDO] Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893642 is a reply to message #893639] |
Thu, 05 July 2012 04:57  |
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Am 05.07.2012 06:13, schrieb Apirom Na Nakorn:
> Hi,
>
> I try to commit data(65535 elements for each client and the size of each element is 1KB) from 4 clients
> simultaneously to 4 resource path under the same repository in CDO Server (4.1), but I get IOTimeoutException so I set
> the new timout in session.options().getNet4jProtocol().setTimeout() to ISignalProtocol.NO_TIMEOUT and run again.
Hmm, I'd have expected a call setCommitTimeout() fixes it.
> This time I get an exception as follow :
>
> Caused by: org.eclipse.emf.cdo.util.CommitException: Rollback in DBStore: java.lang.OutOfMemoryError: GC overhead
> limit exceeded
I've never seen this exception before but Google brings up answers like this:
http://stackoverflow.com/questions/5839359/java-lang-outofmemoryerror-gc-overhead-limit-exceeded
What's the exact command line you're starting the server with?
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
> at java.lang.StringCoding$StringDecoder.decode(Unknown Source)
> at java.lang.StringCoding.decode(Unknown Source)
> at java.lang.String.<init>(Unknown Source)
> at java.lang.String.<init>(Unknown Source)
> at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:754)
> at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:707)
> at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:4718)
> at org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.ObjectTypeTable.putObjectType(ObjectTypeTable.java:116)
> at
> org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.DelegatingObjectTypeMapper.putObjectType(DelegatingObjectTypeMapper.java:68)
> at
> org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.AbstractHorizontalMappingStrategy.putObjectType(AbstractHorizontalMappingStrategy.java:81)
> at
> org.eclipse.emf.cdo.server.internal.db.mapping.horizontal.HorizontalBranchingClassMapping.writeRevision(HorizontalBranchingClassMapping.java:763)
> at org.eclipse.emf.cdo.server.internal.db.DBStoreAccessor.writeRevision(DBStoreAccessor.java:583)
> at org.eclipse.emf.cdo.server.internal.db.DBStoreAccessor.writeRevisions(DBStoreAccessor.java:563)
> at org.eclipse.emf.cdo.spi.server.StoreAccessor.doWrite(StoreAccessor.java:94)
> at org.eclipse.emf.cdo.spi.server.StoreAccessorBase.write(StoreAccessorBase.java:149)
>
> How to solve this problem ?
>
> Thanks in advance
>
> Neung
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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| Re: [CDO]Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893675 is a reply to message #893667] |
Thu, 05 July 2012 08:25 |
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Am 05.07.2012 10:05, schrieb Apirom Na Nakorn:
> Dear Eike
>
> I start CDO Server with option -XX:-UseGCOverheadLimit and wait for the server to run. Now, it's about 2 hours and
> the server is running without throwing the exception, but 1 client already died because out of memory error. BTW, the
> accept solution for the post you mention suggest that
>
> 1. Specify more memory like you mentioned, try something in between like -Xmx512m first
> 2. Work with smaller batches of HashMap objects to process at once if possible
> 3. If you have a lot of duplicate strings, use intern() on them before putting them into the HashMap
> 4. Use the HashMap(int initialCapacity, float loadFactor) constructor to tune for your case
>
> for no.1 I already done with 6GB, but for the rest I'm not sure how to do it. So, I go with the option
> -XX:-UseGCOverheadLimit
I mostly wanted to refer to the -XX:-UseGCOverheadLimit option.
You should generally try to keep the commit size as small as possible, depending on the heap size that you assign.
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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| Re: [CDO]Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893700 is a reply to message #893693] |
Thu, 05 July 2012 10:09 |
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Am 05.07.2012 11:56, schrieb Apirom Na Nakorn:
> Dear Eike
>
> After the long running, CDO Server throw the exception as follow :
>
> monitor-timer [debug.signal] Progress of signal 10: totalWork=100, work=0.554
> Exception in thread "monitor-timer" java.lang.OutOfMemoryError: Direct buffer memory
> at java.nio.Bits.reserveMemory(Bits.java:632)
> at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:97)
> at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:288)
> at org.eclipse.internal.net4j.buffer.Buffer.<init>(Buffer.java:58)
> at org.eclipse.internal.net4j.buffer.BufferFactory.doProvideBuffer(BufferFactory.java:37)
> at org.eclipse.internal.net4j.buffer.BufferProvider.provideBuffer(BufferProvider.java:51)
> at org.eclipse.internal.net4j.buffer.BufferPool.doProvideBuffer(BufferPool.java:137)
> at org.eclipse.internal.net4j.buffer.BufferProvider.provideBuffer(BufferProvider.java:51)
> at org.eclipse.spi.net4j.Connector.provideBuffer(Connector.java:294)
> at org.eclipse.spi.net4j.Channel.provideBuffer(Channel.java:241)
> at org.eclipse.net4j.signal.SignalProtocol$SignalOutputStream$1.provideBuffer(SignalProtocol.java:607)
> at org.eclipse.net4j.buffer.BufferOutputStream.ensureBufferPrivate(BufferOutputStream.java:209)
> at org.eclipse.net4j.buffer.BufferOutputStream.write(BufferOutputStream.java:105)
> at java.io.DataOutputStream.writeInt(DataOutputStream.java:180)
> at org.eclipse.net4j.signal.MonitorProgressRequest.requesting(MonitorProgressRequest.java:47)
> at org.eclipse.net4j.signal.Request.doExtendedOutput(Request.java:65)
> at org.eclipse.net4j.signal.Signal.doOutput(Signal.java:296)
> at org.eclipse.net4j.signal.Request.doExecute(Request.java:57)
> at org.eclipse.net4j.signal.SignalActor.execute(SignalActor.java:51)
> at org.eclipse.net4j.signal.Signal.runSync(Signal.java:251)
> at org.eclipse.net4j.signal.SignalProtocol.startSignal(SignalProtocol.java:433)
> at org.eclipse.net4j.signal.Request.sendAsync(Request.java:51)
> at org.eclipse.net4j.signal.IndicationWithMonitoring$ReportingMonitor.sendProgress(IndicationWithMonitoring.java:161)
> at org.eclipse.net4j.signal.IndicationWithMonitoring$ReportingMonitor.access$0(IndicationWithMonitoring.java:157)
> at org.eclipse.net4j.signal.IndicationWithMonitoring$ReportingMonitor$1.run(IndicationWithMonitoring.java:127)
> at java.util.TimerThread.mainLoop(Timer.java:512)
> at java.util.TimerThread.run(Timer.java:462)
>
> Is it possible to solve this problem ?
I fear not without analyzing your server with a memory profiler ;-(
You could change the BufferPool to keep preallocated buffers around. How many buffers are in your pool when it goes on
strike?
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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| Re: [CDO]Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893708 is a reply to message #893700] |
Thu, 05 July 2012 10:34 |
Apirom Na Nakorn
Messages: 14
Registered: July 2012 |
Junior Member |
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Dear Eike
I am quite new to CDO and Net4J, how can I find this number of preallocated buffers for BufferPool ?
I grab some of the log before the exception as follow:
monitor-timer [debug.channel] Handling buffer: Buffer@32,500[PUTTING] --> Channel[1, SERVER, cdo]
monitor-timer [debug.signal] ================ Requesting: Signal[protocol=cdo, id=-3, name=MonitorProgressRequest, correlation=15,849]
monitor-timer [debug.signal] Progress of signal 10: totalWork=100, work=0.554
Exception in thread "monitor-timer" java.lang.OutOfMemoryError: Direct buffer memory
Is 32,500 be the number of buffers just before the exception ?
Thanks in advance
Neung
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| Re: [CDO]Encounter java.lang.OutOfMemoryError: GC overhead limit exceeded when commit from 4 clients [message #893716 is a reply to message #893708] |
Thu, 05 July 2012 10:52 |
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Am 05.07.2012 12:34, schrieb Apirom Na Nakorn:
> Dear Eike
>
> I am quite new to CDO and Net4J, how can I find this number of preallocated buffers for BufferPool ?
>
> I grab some of the log before the exception as follow:
>
> monitor-timer [debug.channel] Handling buffer: Buffer@32,500[PUTTING] --> Channel[1, SERVER, cdo]
> monitor-timer [debug.signal] ================ Requesting: Signal[protocol=cdo, id=-3, name=MonitorProgressRequest,
> correlation=15,849]
> monitor-timer [debug.signal] Progress of signal 10: totalWork=100, work=0.554
> Exception in thread "monitor-timer" java.lang.OutOfMemoryError: Direct buffer memory
>
> Is 32,500 be the number of buffers just before the exception ?
No. You need to find out the value of org.eclipse.internal.net4j.buffer.BufferPool.pooledBuffers before or when the
exception occurs, or continuously.
Googling for "java.lang.OutOfMemoryError: Direct buffer memory" immediately gave me a hint about this JVM option:
-XX:MaxDirectMemorySize=<size>
Do you know Google? :P
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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