Thread: prepareCall hangs

Hi
I have a an application that uses a lot of stored functions, some of them which create temporary tables and refcursors that point to the tables. Something that comes up occasionally are errors like

the jdbc code looks like      
        Connection con = poolingDataSource.getConnection();
        con.setAutoCommit(false);
        CallableStatement proc = con.prepareCall("{ ? = call \"insAccount\" ( ? ) }");

        proc.registerOutParameter(1, Types.OTHER);
        proc.setString(2,userName);
        this.registerCallableStatementForCancel(proc);
        logger.debug("registerCallableStatementForCancel(): exit"+userName);
/* another thread will call statement.cancel() if timeout exceeded*/
        proc.execute();
        this.unregisterCallableStatementForCancel(proc);
        logger.debug("unregisterCallableStatementForCancel(): exit"+userName);
        ResultSet rset = (ResultSet)proc.getObject(1);

Akhil Srinivasan wrote:

>         CallableStatement proc = con.prepareCall("{ ? = call
> \"insAccount\" ( ? ) }");
>
>         proc.registerOutParameter(1, Types.OTHER);
>         proc.setString(2,userName);
>         this.registerCallableStatementForCancel(proc);
>         logger.debug("registerCallableStatementForCancel(): exit"+userName);
> /* another thread will call statement.cancel() if timeout exceeded*/
>         proc.execute();
>         this.unregisterCallableStatementForCancel(proc);
>         logger.debug("unregisterCallableStatementForCancel():
> exit"+userName);
>         ResultSet rset = (ResultSet)proc.getObject(1);
>

> Occasionally the prepareCall just hangs, as logging statements show that
> it does not enter the execute().

I find this unlikely as prepareCall doesn't do any I/O or thread-related
work. It could be getting stuck in a loop, but it seems odd that it
would only happen intermittently. More likely seems to be that you have
a problem in registerCallableStatementForCancel.

Can you add more logging immediately before calling
registerCallableStatementForCancel() to eliminate that possibility?

Alternatively, can you get a thread dump (on Linux/Solaris, send a
SIGQUIT to the Java process) when it hangs? That'd show us exactly where
things have stopped.

-O

Hi,
Problem solved, the connection pool was running out of connections as we were catching the exception after the connections were released.
Thanks to all for the help.

Akhil Srinivasan