[Cayenne-user] Transaction STATUS problem

Hi,
I have a very strange problem with Cayenne 3.0 and Derby Embedded database.
When i execute my application, first runs a query, then when runs the second
one (different from first), it raise this exception:

Exception in thread "Thread-5" org.apache.cayenne.CayenneRuntimeException:
[v.3.0 Apr 26 2010 09:59:17] Global exception.
at
org.apache.cayenne.access.DataDomainQueryAction.nextGlobalException(DataDomainQueryAction.java:553)
at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:258)
at
org.apache.cayenne.access.DataDomainQueryAction.runQuery(DataDomainQueryAction.java:422)
at
org.apache.cayenne.access.DataDomainQueryAction.access$000(DataDomainQueryAction.java:69)
at
org.apache.cayenne.access.DataDomainQueryAction$2.transform(DataDomainQueryAction.java:395)
at
org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:840)
at
org.apache.cayenne.access.DataDomainQueryAction.runQueryInTransaction(DataDomainQueryAction.java:392)
at
org.apache.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:121)
at org.apache.cayenne.access.DataDomain.onQuery(DataDomain.java:743)
at
org.apache.cayenne.util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:333)
at
org.apache.cayenne.util.ObjectContextQueryAction.execute(ObjectContextQueryAction.java:96)
at org.apache.cayenne.access.DataContext.onQuery(DataContext.java:1278)
at org.apache.cayenne.access.DataContext.performQuery(DataContext.java:1267)
at minica.server.actions.CANewCertAction.doAction(CANewCertAction.java:46)
at
minica.server.parsers.CANewCertParser.parseMessage(CANewCertParser.java:37)
at minica.server.CASocketReceiver.run(CASocketReceiver.java:73)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalStateException: Transaction must have
'STATUS_ACTIVE' to add a connection. Current status: STATUS_COMMITTED
at
org.apache.cayenne.access.ExternalTransaction.addConnection(ExternalTransaction.java:64)
at
org.apache.cayenne.access.DataNode$TransactionDataSource.getConnection(DataNode.java:365)
at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:248)
... 15 more

The second query is executed in a different thread.
This is a code I use to get the DataContext object:

public ObjectContext getContext() {
try {
return BaseContext.getThreadObjectContext();
} catch(IllegalStateException e) {

BaseContext.bindThreadObjectContext(DataContext.createDataContext(false));
return BaseContext.getThreadObjectContext();
}
}

Both queries are simply SelectQuery:

1.
ObjectContext context =
CertificationAuthority.getInstance().getContext();
SelectQuery select1 = new SelectQuery(DBCertificate.class);
List<DBCertificate> l = context.performQuery(select1);

2.
ObjectContext context =
CertificationAuthority.getInstance().getContext();
Expression clause = ExpressionFactory.matchExp(DBUser.NAME_PROPERTY,
subject);
SelectQuery query = new SelectQuery(DBUser.class, clause);
List<DBUser> result = context.performQuery(query);

The very strange thing is that the app raises exception only at first time,
when DB is empty and, more strange, if I execute in debug mode, all works
well !
I try anything but I don't find any solution.

Any suggestions?

*Andrea*

Sorry for double post, it's my first time :)
Anyway, I solve the problem using H2 instead of Derby and, for now, all
works like a charm!

2010/6/8 Andrea Pavan <[email protected]>

This seems like a race condition, and I am not sure that switching the
DB fixes it. I just don't understand how it can possibly happen. Do
you have "Container Managed Transactions" set to on by any chance?

Andrus

No, "Container Managed Transactions" isn't checked.

2010/6/8 Andrus Adamchik <[email protected]>

As you said, the problem persist also with H2, even if it happens many time
less, maybe because H2 executes queries faster.
I synchronized the method for obtaining the thread bounded DataContext, but
the problem still persist.
Have I to synchronize also the method that creates and performs query?

Thanks for help.

*Andrea*

2010/6/9 Andrea Pavan <[email protected]>

Actually no, and this is what makes it so strange. DataContext is
thread-safe for read operations, so multiple threads can access it
simultaneously. Transactions are bound to threads, and unbound in the
finally block, so overlapping transactions between threads should not
be possible, neither are overlapping transactions within a thread.

So anything else special/customized about your transactions? In any
event In recommend running your app in debugger and putting a
breakpoint in DataDomain.runInTransaction(..) to check what really
happens.

Andrus