Hi Luca, Could you please clarify more details for Caching, including the difference between Level 1 and Level 2 cache? I read the http://orientdb.com/docs/last/Caching.html, and found it is not clear to describe the several cache mechanisms in OrientDB, but I found another wiki @ https://github.com/sslavic/orientdb-wiki/blob/master/Caching.md, it told me more about caching, but I don't know it is workable for the latest OrientDB version, such as 2.2.xx, because I am investigating the CME issues in OrientDB 2.2.12.
Thank you very much, Zhiqiang 在 2012年6月19日星期二 UTC+8上午2:49:31，Lvc@写道： > > Hi, > 1) http://code.google.com/p/orient/wiki/Caching > 2) usually yes: if the mvcc breaks means you could work on old records > > Lvc@ > > On 18 June 2012 20:44, Yanxin <[email protected] <javascript:>> wrote: > >> Thank you so much, Luca. >> Several questions:) >> 1) What is the purpose of cache level 1 and level 2? >> 2) should I enable mvcc when I run my java program? >> >> >> On Monday, June 18, 2012 1:46:23 AM UTC-7, Lvc@ wrote: >>> >>> Hi, >>> you should disable the mvcc in the server side too. However usually >>> disabling mvcc is not a good solution because you could update not last >>> version loosing changes. >>> >>> On high concurrency scenario the best is: >>> >>> 1. disable level2 cache on clients (in the 1.1 or 1.2 we'll have a >>> distributed level2 cache) >>> 2. force reloading of vertexes in case of concurrency exception. >>> Example: >>> >>> // 10 is the max retry here >>> for( int i = 0; i < 10; ++i ){ >>> try{ >>> // APPLY YOUR CHANGES >>> db.createEdge( v1, v2 ); >>> } catch( OConcurrentModificationException e ){ >>> // RELOAD VERTEXES >>> v1.reload(); >>> v2.reload(); >>> } >>> } >>> >>> Lvc@ >>> >>> On 17 June 2012 09:02, Yanxin <[email protected] <javascript:>> wrote: >>> >>>> Hello, >>>> I have a program to insert record into OrientDB, which use timestamp as >>>> input parameters. >>>> Originallly when I run the program, it will stops in the middle and >>>> report "com.orientechnologies.orient.core.exception. >>>> OConcurrentModificationException" error. >>>> I google it and find the solution, which disable level1 cache and mvcc. >>>> This solve my problem. >>>> For example, >>>> java -Dcache.level1.enabled=false -Ddb.mvcc=false UpdateGraph >>>> 2012-06-01 2012-0614 >>>> >>>> I have run it for a week without the problem. >>>> >>>> However, I have another question now. I need to run the program to >>>> update graph in different days at the same time so that I can speed up my >>>> progress, for example， I need to run >>>> java -Dcache.level1.enabled=false -Ddb.mvcc=false UpdateGraph >>>> 2012-06-13 2012-0614 >>>> java -Dcache.level1.enabled=false -Ddb.mvcc=false UpdateGraph >>>> 2012-06-14 2012-0615 >>>> >>>> at the same time. The issue is when I start second process, the first >>>> one terminated with the same error as before "com.orientechnologies.orient. >>>> core.exception.OConcurrentModificationException". >>>> >>>> Could anyone help me to solve the issue? >>>> Thanks a lot. >>>> Yanxin >>>> >>>> >>>> Exception in thread "main" com.orientechnologies.orient.core.exception. >>>> OConcurrentModificationException: Cannot update record #14:69 in >>>> storage 'graph' because the version is not the latest. Probably you are >>>> updating an old record or it has been modified by another user (db=v81 >>>> your=v80) >>>> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native >>>> Method) >>>> at sun.reflect.NativeConstructorAccessorImpl.newInstance( >>>> NativeConstructorAccessorImpl.java:57) >>>> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance( >>>> DelegatingConstructorAccessorImpl.java:45) >>>> at java.lang.reflect.Constructor.newInstance(Constructor.java: >>>> 532) >>>> at com.orientechnologies.orient.enterprise.channel.binary. >>>> OChannelBinary.createException(OChannelBinary.java:411) >>>> at com.orientechnologies.orient.enterprise.channel.binary. >>>> OChannelBinary.handleStatus(OChannelBinary.java:364) >>>> at com.orientechnologies.orient.enterprise.channel.binary. >>>> OChannelBinaryAsynch.beginResponse(OChannelBinaryAsynch.java:145) >>>> at com.orientechnologies.orient.enterprise.channel.binary. >>>> OChannelBinaryAsynch.beginResponse(OChannelBinaryAsynch.java:60) >>>> at com.orientechnologies.orient.client.remote.OStorageRemote. >>>> beginResponse(OStorageRemote.java:1492) >>>> at com.orientechnologies.orient.client.remote.OStorageRemote. >>>> updateRecord(OStorageRemote.java:445) >>>> at com.orientechnologies.orient.client.remote. >>>> OStorageRemoteThread.updateRecord(OStorageRemoteThread.java:151) >>>> at com.orientechnologies.orient.core.db.raw.ODatabaseRaw.save( >>>> ODatabaseRaw.java:243) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordAbstract.executeSaveRecord(ODatabaseRecordAbstract.java: >>>> 662) >>>> at com.orientechnologies.orient.core.tx.OTransactionNoTx. >>>> saveRecord(OTransactionNoTx.java:72) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:221) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:214) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:35) >>>> at com.orientechnologies.orient.core.serialization.serializer. >>>> record.string.ORecordSerializerCSVAbstract.linkToStream( >>>> ORecordSerializerCSVAbstract.java:739) >>>> at com.orientechnologies.orient.core.serialization.serializer. >>>> record.string.ORecordSerializerCSVAbstract.fieldToStream( >>>> ORecordSerializerCSVAbstract.java:246) >>>> at com.orientechnologies.orient.core.serialization.serializer. >>>> record.string.ORecordSerializerSchemaAware2CSV.toString( >>>> ORecordSerializerSchemaAware2CSV.java:242) >>>> at com.orientechnologies.orient.core.serialization.serializer. >>>> record.string.ORecordSerializerStringAbstract.toStream( >>>> ORecordSerializerStringAbstract.java:80) >>>> at com.orientechnologies.orient.core.record. >>>> ORecordSchemaAwareAbstract.toStream(ORecordSchemaAwareAbstract. >>>> java:118) >>>> at com.orientechnologies.orient.core.record. >>>> ORecordSchemaAwareAbstract.toStream(ORecordSchemaAwareAbstract. >>>> java:113) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordAbstract.executeSaveRecord(ODatabaseRecordAbstract.java: >>>> 616) >>>> at com.orientechnologies.orient.core.tx.OTransactionNoTx. >>>> saveRecord(OTransactionNoTx.java:72) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:221) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:214) >>>> at com.orientechnologies.orient.core.db.record. >>>> ODatabaseRecordTx.save(ODatabaseRecordTx.java:35) >>>> at com.orientechnologies.orient.core.record.ORecordAbstract. >>>> save(ORecordAbstract.java:269) >>>> at com.orientechnologies.orient.core.record.impl.ODocument. >>>> save(ODocument.java:1233) >>>> at com.orientechnologies.orient.core.record.impl.ODocument. >>>> save(ODocument.java:1222) >>>> at com.orientechnologies.orient.core.record.impl.ODocument. >>>> save(ODocument.java:69) >>>> at com.orientechnologies.orient.core.type.tree.OMVRBTreeRID. >>>> saveAllNewEntries(OMVRBTreeRID.java:364) >>>> at com.orientechnologies.orient.core.type.tree.OMVRBTreeRID. >>>> commitChanges(OMVRBTreeRID.java:307) >>>> at com.orientechnologies.orient.core.type.tree. >>>> OMVRBTreePersistent.put(OMVRBTreePersistent.java:474) >>>> at com.orientechnologies.orient.core.type.tree. >>>> OMVRBTreeRIDSet.add(OMVRBTreeRIDSet.java:109) >>>> at com.orientechnologies.orient.core.db.graph.OGraphDatabase. >>>> createEdge(OGraphDatabase.java:275) >>>> at com.orientechnologies.orient.core.db.graph.OGraphDatabase. >>>> createEdge(OGraphDatabase.java:244) >>>> >>>> >>> > -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. 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