Hello.
I have moved the thread to cayenne-dev.
This is interesting. It reminds me of the different ways to
concurrency control in a database :) PostgreSQL MVCC being one of the
best.
http://www.postgresql.org/docs/current/static/mvcc-intro.html
Do we need to lock the DataRowStore for the duration of the commit?
Would it be possible to only update the cache after the db-commit are
finished and let the DataRowStore return old data while committing?
What are the status of "I think we will be changing cache format from
DataRows (that cache DB data) to some kind of object property-based
"rows""?
http://www.objectstyle.org/cayenne/lists/cayenne-devel/2006/04/0248.html
- Tore.
On Dec 12, 2006, at 13:21 , Andrus Adamchik wrote:
> * On commit, DRS is locked for the duration of the query execution
> (DataDomainFlushAction.flush())
> * On select, DRS is locked AFTER the query for the duration of the
> row-to-object conversion
>
> So yes, slow commits will block object queries.
>
> Hmm... I wonder if we can do cache update on select in a thread
> separate from the calling thread (via EventManager?), and avoid
> locking during object creation..? This should generally improve
> throughput. Something to think about.
>
> Alternatively for slow commits you can try to use a special
> DataContext that uses its own local instance of DataRowStore
> (passed in ObjectStore constructor), thus avoiding a shared lock.
>
> Andrus
>
>
> On Dec 12, 2006, at 1:48 PM, Tore Halset wrote:
>> Hello.
>>
>> One of our applications blocked for some time today. It worked out
>> fine after a couple of minutes. It is running cayenne-1.2. We will
>> upgrade to 2.0.1 in the start of january. The attached stacktraces
>> are extracted using JBoss jmx-console.
>>
>> Thread http-0.0.0.0-80-6 are performing a slow
>> DataContext.commitChanges. It locks our MS SQL Server for some
>> minutes. I guess we will be able to optimize this by deleting some
>> old records or creating a index.
>>
>> Some other threads are performing simple queries, but are blocked
>> by a lock in DataRowStore. Are all (other) queries blocked while
>> doing a commitChanges? I have seen some discussion around locks in
>> DataRowStore lately, but I do not know if this is related.
>>
>> - Tore.
>>
>> Thread: http-0.0.0.0-80-3 : priority:5, demon:true, threadId:38,
>> threadState:BLOCKED,
>> threadLockName:org.objectstyle.cayenne.access.DataRowStor..a2ae9
>> org.objectstyle.cayenne.access.DataRowStore.getCachedSnapshot
>> (DataRowStore.java:387)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.interceptOIDQuer
>> y(DataDomainQueryAction.java:164)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.execute
>> (DataDomainQueryAction.java:142)
>> org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:
>> 766)
>> org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery
>> (ObjectContextQueryAction.java:253)
>> org.objectstyle.cayenne.access.DataContextQueryAction.execute
>> (DataContextQueryAction.java:90)
>> org.objectstyle.cayenne.access.DataContext.onQuery
>> (DataContext.java:1422)
>> org.objectstyle.cayenne.access.DataContext.performQuery
>> (DataContext.java:1411)
>> org.objectstyle.cayenne.DataObjectUtils.objectForQuery
>> (DataObjectUtils.java:290)
>> org.objectstyle.cayenne.DataObjectUtils.objectForPK
>> (DataObjectUtils.java:276)
>> org.objectstyle.cayenne.DataObjectUtils.objectForPK
>> (DataObjectUtils.java:185)
>>
>> Thread: http-0.0.0.0-443-2 : priority:5, demon:true, threadId:47,
>> threadState:BLOCKED,
>> threadLockName:org.objectstyle.cayenne.access.DataRowStor..a2ae9
>> org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFrom
>> DataRows(ObjectResolver.java:133)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectC
>> onversion(DataDomainQueryAction.java:373)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.execute
>> (DataDomainQueryAction.java:151)
>> org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:
>> 766)
>> org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery
>> (ObjectContextQueryAction.java:253)
>> org.objectstyle.cayenne.access.DataContextQueryAction.execute
>> (DataContextQueryAction.java:90)
>> org.objectstyle.cayenne.access.DataContext.onQuery
>> (DataContext.java:1422)
>> org.objectstyle.cayenne.access.DataContext.performQuery
>> (DataContext.java:1411)
>> org.objectstyle.cayenne.access.ToManyList.resolvedObjectList
>> (ToManyList.java:343)
>> org.objectstyle.cayenne.access.ToManyList.size(ToManyList.java:296)
>>
>> Thread: EventDispatchThread-0 : priority:5, demon:true, threadId:
>> 54, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..2cd2e
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-1 : priority:5, demon:true, threadId:
>> 55, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..2cd2e
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-2 : priority:5, demon:true, threadId:
>> 56, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..2cd2e
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-3 : priority:5, demon:true, threadId:
>> 57, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..2cd2e
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-4 : priority:5, demon:true, threadId:
>> 58, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..2cd2e
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-0 : priority:5, demon:true, threadId:
>> 59, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..9bfa
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: EventDispatchThread-1 : priority:5, demon:true, threadId:
>> 60, threadState:WAITING, threadLockName:java.util.Collections
>> $SynchronizedLis..9bfa
>> java.lang.Object.wait(Native Method)
>> java.lang.Object.wait(Object.java:474)
>> org.objectstyle.cayenne.event.EventManager$DispatchThread.run
>> (EventManager.java:486)
>>
>> Thread: http-0.0.0.0-443-15 : priority:5, demon:true, threadId:
>> 104, threadState:BLOCKED,
>> threadLockName:org.objectstyle.cayenne.access.ToManyLis..77348f
>> org.objectstyle.cayenne.access.ToManyList.resolvedObjectList
>> (ToManyList.java:332)
>> org.objectstyle.cayenne.access.ToManyList.size(ToManyList.java:296)
>>
>> Thread: http-0.0.0.0-80-6 : priority:5, demon:true, threadId:113,
>> threadState:RUNNABLE, threadLockName:null
>> java.net.SocketInputStream.socketRead0(Native Method)
>> java.net.SocketInputStream.read(SocketInputStream.java:129)
>> java.io.DataInputStream.readFully(DataInputStream.java:176)
>> java.io.DataInputStream.readFully(DataInputStream.java:152)
>> net.sourceforge.jtds.jdbc.SharedSocket.readPacket
>> (SharedSocket.java:814)
>> net.sourceforge.jtds.jdbc.SharedSocket.getNetPacket
>> (SharedSocket.java:695)
>> net.sourceforge.jtds.jdbc.ResponseStream.getPacket
>> (ResponseStream.java:443)
>> net.sourceforge.jtds.jdbc.ResponseStream.read(ResponseStream.java:
>> 102)
>> net.sourceforge.jtds.jdbc.ResponseStream.peek(ResponseStream.java:87)
>> net.sourceforge.jtds.jdbc.TdsCore.wait(TdsCore.java:3772)
>> net.sourceforge.jtds.jdbc.TdsCore.executeSQL(TdsCore.java:1031)
>> net.sourceforge.jtds.jdbc.JtdsStatement.executeSQL
>> (JtdsStatement.java:436)
>> net.sourceforge.jtds.jdbc.JtdsPreparedStatement.executeUpdate
>> (JtdsPreparedStatement.java:402)
>> org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeUpdat
>> e(WrappedPreparedStatement.java:227)
>> org.objectstyle.cayenne.access.jdbc.BatchAction.runAsIndividualQuerie
>> s(BatchAction.java:224)
>> org.objectstyle.cayenne.access.jdbc.BatchAction.performAction
>> (BatchAction.java:117)
>> org.objectstyle.cayenne.dba.sqlserver.SQLServerBatchAction.performAct
>> ion(SQLServerBatchAction.java:95)
>> org.objectstyle.cayenne.access.DataNodeQueryAction.runQuery
>> (DataNodeQueryAction.java:95)
>> org.objectstyle.cayenne.access.DataNode.performQueries
>> (DataNode.java:309)
>> org.objectstyle.cayenne.access.DataDomainFlushAction.runQueries
>> (DataDomainFlushAction.java:255)
>> org.objectstyle.cayenne.access.DataDomainFlushAction.flush
>> (DataDomainFlushAction.java:177)
>> org.objectstyle.cayenne.access.DataDomain.onSyncFlush
>> (DataDomain.java:830)
>> org.objectstyle.cayenne.access.DataDomain$2.transform
>> (DataDomain.java:801)
>> org.objectstyle.cayenne.access.DataDomain.runInTransaction
>> (DataDomain.java:856)
>> org.objectstyle.cayenne.access.DataDomain.onSync(DataDomain.java:798)
>> org.objectstyle.cayenne.access.DataContext.flushToParent
>> (DataContext.java:1261)
>> org.objectstyle.cayenne.access.DataContext.commitChanges
>> (DataContext.java:1165)
>>
>> Thread: http-0.0.0.0-443-18 : priority:5, demon:true, threadId:
>> 187, threadState:BLOCKED,
>> threadLockName:org.objectstyle.cayenne.access.DataRowStor..a2ae9
>> org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFrom
>> DataRows(ObjectResolver.java:133)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectC
>> onversion(DataDomainQueryAction.java:373)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.execute
>> (DataDomainQueryAction.java:151)
>> org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:
>> 766)
>> org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery
>> (ObjectContextQueryAction.java:253)
>> org.objectstyle.cayenne.access.DataContextQueryAction.execute
>> (DataContextQueryAction.java:90)
>> org.objectstyle.cayenne.access.DataContext.onQuery
>> (DataContext.java:1422)
>> org.objectstyle.cayenne.access.DataContext.performQuery
>> (DataContext.java:1411)
>>
>> Thread: http-0.0.0.0-443-19 : priority:5, demon:true, threadId:
>> 188, threadState:BLOCKED,
>> threadLockName:org.objectstyle.cayenne.access.DataRowStor..a2ae9
>> org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFrom
>> DataRows(ObjectResolver.java:133)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectC
>> onversion(DataDomainQueryAction.java:373)
>> org.objectstyle.cayenne.access.DataDomainQueryAction.execute
>> (DataDomainQueryAction.java:151)
>> org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:
>> 766)
>> org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery
>> (ObjectContextQueryAction.java:253)
>> org.objectstyle.cayenne.access.DataContextQueryAction.execute
>> (DataContextQueryAction.java:90)
>> org.objectstyle.cayenne.access.DataContext.onQuery
>> (DataContext.java:1422)
>> org.objectstyle.cayenne.access.DataContext.performQuery
>> (DataContext.java:1411)
>>
>>
>
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