[hibernate-dev] Using AS7 prepared Statement caching and Hibernate 4.0.0.Beta4 + 4.0.0.Beta5

[Gail Badner]

Here are two logs that should help track down the problem if it is in Hibernate:
- org.hibernate.engine.jdbc.internal.JdbcResourceRegistryImpl (trace)
- org.hibernate.SQL (debug).

Gail

----- Original Message -----
> From: "Scott Marlow" <smarlow at redhat.com>
> To: hibernate-dev at lists.jboss.org, "Jeremy Whiting" <jwhiting at redhat.com>
> Sent: Tuesday, September 20, 2011 7:22:57 AM
> Subject: Re: [hibernate-dev] Using AS7 prepared Statement caching and Hibernate 4.0.0.Beta4 + 4.0.0.Beta5
> 
> This went away for a while but Jeremy is now recreating this
> (http://pastie.org/2563226).
> 
> Can anyone tell us how long Hibernate 4.0.0 can hold onto a
> PreparedStatement?  And whether its possible that Hibernate may be
> holding onto a PreparedStatement for reuse after Hibernate has called
> the PreparedStatement.close method?
> 
> This problem goes away, if the AS7 PreparedStatement cache is
> disabled
> but for best performance, it would be nice to support using Hibernate
> with a PreparedStatement cache.
> 
> Its possible that the bug is also in the AS7 PreparedStatement cache
> and
> that we just haven't found it yet.
> 
> What do you think?
> 
> Thanks,
> Scott
> 
> On 08/04/2011 03:41 PM, Scott Marlow wrote:
> > Let me add, that in theory, the AS7 prepared statement cache,
> > should not
> > close the prepared statements while they are in use by Hibernate.
> > Currently in AS7, if the cache fills up, the statement should be
> > removed
> > from the pool but not closed.
> >
> > I still would like to understand why the prepared statement is
> > getting
> > closed while its still being used.
> >
> > On 08/04/2011 10:00 AM, Scott Marlow wrote:
> >> https://issues.jboss.org/browse/AS7-1461 reflects a problem
> >> reported by
> >> two users.  One user reported, that in a transaction that included
> >> multiple different entities being created, that Hibernate is
> >> trying to
> >> use a closed prepared statement.
> >>
> >> My question at this point is, what would happen if the AS7
> >> prepared
> >> statement cache were to close a prepared statement during a
> >> transaction.
> >>
> >> For example, assuming that the prepared statement cache was
> >> configured
> >> to a very low limit, like two.  After two unique sql statements
> >> are in
> >> the prepared statement cache, when a third unique sql statement is
> >> created, one of the two cached statements will be closed.  Could
> >> Hibernate be holding onto one of these cached prepared statements
> >> (for
> >> reuse in the transaction) that are closed?
> >>
> >> Example execution order from user report:
> >>
> >> 1.  insert into ASSEMBLIES (NAME, A_ID) values (?, ?)
> >>
> >> 2.  other sql statements are executed.
> >>
> >> 3.  insert into ASSEMBLIES (NAME, A_ID) values (?, ?)
> >>
> >> 4.  other sql statements are executed.
> >>
> >> 5.  At this point, I believe that "insert into ASSEMBLIES (NAME,
> >> A_ID)
> >> values (?, ?)" could be aged out of the AS7 prepared statement
> >> cache.
> >>
> >> 6.  "insert into ASSEMBLIES (NAME, A_ID) values (?, ?)" fails to
> >> execute
> >> because of error
> >> "com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:
> >> No operations allowed after statement closed"
> >>
> >> For my local testing, I'm using H2 and get error
> >> "org.h2.jdbc.JdbcSQLException: The object is already closed
> >> [90007-145]"
> >>
> >> Does/should Hibernate check the prepared statement to see if its
> >> have
> >> been closed before its reused in a transaction?  Or should users
> >> disable
> >> the AS7 prepared statement cache (current workaround)?
> >>
> >> If Hibernate is currently checking if the prepared statement is
> >> closed
> >> before reusing it, I must of missed that code in my inspection.
> >>
> >> At this point, I'm still trying to find the root cause and answer
> >> the
> >> above question as well.
> >>
> >> Scott
> >> _______________________________________________
> >> hibernate-dev mailing list
> >> hibernate-dev at lists.jboss.org
> >> https://lists.jboss.org/mailman/listinfo/hibernate-dev
> >
> > _______________________________________________
> > hibernate-dev mailing list
> > hibernate-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> 
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