Here's the code I'm currently using, it's based on the v3 with generics
version I got from the repo a few days earlier :
DataContext context = DataContext.createDataContext();
SelectQuery query = new SelectQuery(ItemDetail.class);
//query.andQualifier( ExpressionFactory.matchDbExp(
ItemDetail.PROFILEID_PK_COLUMN, 10 ) );
//query.andQualifier( ExpressionFactory.likeExp(
ItemDetail.NAME_PROPERTY, "G%")) ;
query.addOrdering(ItemDetail.NAME_PROPERTY, Ordering.ASC );
query.setCursorFetchSize( 1000 );
ResultIterator iterator = context.performIteratedQuery(query);
while( iterator.hasNextRow())
{
ItemDetail detail = (ItemDetail)context.objectFromDataRow(
ItemDetail.class, (DataRow)iterator.nextRow(), false);
System.out.println( detail.getName() + "\t\t\t\t" +
detail.getKeywords() );
}
It works...
If I remove the fetchSize parameter, it fails with following stackTrace :
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Class.java:2291)
at java.lang.Class.getDeclaredField(Class.java:1880)
at
java.util.concurrent.atomic.AtomicReferenceFieldUpdater$AtomicReferenceFieldUpdaterImpl.<init>(AtomicReferenceFieldUpdater.java:181)
at
java.util.concurrent.atomic.AtomicReferenceFieldUpdater.newUpdater(AtomicReferenceFieldUpdater.java:65)
at java.sql.SQLException.<clinit>(SQLException.java:353)
at
org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1325)
at
org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:194)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:451)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:350)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:254)
at
org.apache.cayenne.access.jdbc.SelectAction.performAction(SelectAction.java:78)
at
org.apache.cayenne.access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:87)
at
org.apache.cayenne.access.DataNode.performQueries(DataNode.java:274)
at
org.apache.cayenne.access.DataDomainLegacyQueryAction.execute(DataDomainLegacyQueryAction.java:79)
at
org.apache.cayenne.access.DataDomain$1.transform(DataDomain.java:713)
at
org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:833)
at
org.apache.cayenne.access.DataDomain.performQueries(DataDomain.java:710)
at
org.apache.cayenne.access.DataContext.internalPerformIteratedQuery(DataContext.java:1213)
at
org.apache.cayenne.access.DataContext.performIteratedQuery(DataContext.java:1179)
at cayenne.CayenneMain.main(CayenneMain.java:43)
I'm surprised that you get different results... I use the lastest 8.3.604
driver from jdbc.
Otherwise, looking at cayenne logs it seems that a transaction is being
started :
INFO: --- will run 1 query.
25 mai 2009 11:58:35 org.apache.cayenne.access.QueryLogger logConnect
INFO: Opening connection: jdbc:postgresql://localhost/prediggo_db
Login: postgres
Password: *******
25 mai 2009 11:58:35 org.apache.cayenne.access.QueryLogger logConnectSuccess
INFO: +++ Connecting: SUCCESS.
25 mai 2009 11:58:35 org.apache.cayenne.access.QueryLogger
logBeginTransaction
INFO: --- transaction started.
25 mai 2009 11:58:36 org.apache.cayenne.access.QueryLogger log
INFO: Detected and installed adapter:
org.apache.cayenne.dba.postgres.PostgresAdapter
25 mai 2009 11:58:36 org.apache.cayenne.access.QueryLogger logQuery
INFO: SELECT t0.timest, t0.keywords,
If you want, I can test your implementation with my test case but I can't
afford to spend much time setting up the build environment (jdk 1.5 + maven
stuff)... If I could get compiled binaries somewhere...
Andrey Razumovsky wrote:
>
> I'm using latest postgres (or mysql) driver. To make a test, I put 1M
> records in db table, then do "select * from that_table". No matter which
> fetch size I tried to set, at the moment of PreparedStastement.execute()
> something about 70-100Mb are allocated (I don't actually remember the
> quantity right now). So, if heap size is small, I get OutOfMemory.
> Otherwise, it's all ok and rows can be quickly iterated. Looking at code
> on
> postgres site, the only difference is that I didn't bother with autocommit
> mode. I'm not sure Cayenne does, too... Maybe this is the reason why I
> didn't get positive results.
>
> Andrey
>
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