I have a weird problem, I am using UserTransaction in JBoss, not from EJB at this time.

I have a working thread A which selects from table T and does several inserts in the table T, all within a user transaction. This thread can take a long time to execute since it is accessing an external system.

While the thread A is running, my web application is accessed and requires to select from table T within its own user transaction. The query hangs until thread A commits its transaction.

I don't set isolation level (so I assume I am using read commited), I use read-only forward-only statements to read the table T from the web request.

What am I doing wrong, why is my user request waiting of thread T to commit the transaction.

I am using the XADataSourceLoader configured for SAP db in JBoss 2.4.4

Pseudo code:

thread T
{
getUserTransaction().begin();
getConnection();
prepareStatement("select ... from T where ...");
...
statement.close();
loop {
//slow network access
prepareStatement("insert into T ...");
...
statement.execute();
statement.close();
}
getUserTransaction().commit();
}

request
{
getUserTransaction().begin();
getConnection();
prepareStatement("select ... from T where ...");
// this waits until thread A commits the transaction
...
getUserTransaction().commit();
}

Thanks for you help,

Benoit