Re: does commitChanges lock all other queries?

Tue, 12 Dec 2006 04:22:44 -0800

* 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:[EMAIL PROTECTED] org.objectstyle.cayenne.access.DataRowStore.getCachedSnapshot (DataRowStore.java:387) org.objectstyle.cayenne.access.DataDomainQueryAction.interceptOIDQuery (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:[EMAIL PROTECTED] org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFromD ataRows(ObjectResolver.java:133) org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectCo nversion(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 [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-1 : priority:5, demon:true, threadId: 55, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-2 : priority:5, demon:true, threadId: 56, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-3 : priority:5, demon:true, threadId: 57, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-4 : priority:5, demon:true, threadId: 58, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-0 : priority:5, demon:true, threadId: 59, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:474)
org.objectstyle.cayenne.event.EventManager$DispatchThread.run (EventManager.java:486)
Thread: EventDispatchThread-1 : priority:5, demon:true, threadId: 60, threadState:WAITING, threadLockName:java.util.Collections [EMAIL PROTECTED] 
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:[EMAIL PROTECTED] 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.executeUpdate (WrappedPreparedStatement.java:227) org.objectstyle.cayenne.access.jdbc.BatchAction.runAsIndividualQueries (BatchAction.java:224) org.objectstyle.cayenne.access.jdbc.BatchAction.performAction (BatchAction.java:117) org.objectstyle.cayenne.dba.sqlserver.SQLServerBatchAction.performActi on(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:[EMAIL PROTECTED] org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFromD ataRows(ObjectResolver.java:133) org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectCo nversion(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:[EMAIL PROTECTED] org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFromD ataRows(ObjectResolver.java:133) org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectCo nversion(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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