Hi,

I'm at my wit's end here-- I updated my application to hibernate 3 and tested it with hsql and postgres. With hsql it works fine, no problems. However with Postgres some errors have started to show up:

Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main] -- caught unexpected Exception while executing posted task.
java.lang.NullPointerException
at org.postgresql.jdbc2.AbstractJdbc2Statement.close(AbstractJdbc2Statement.java:656)
at com.mchange.v1.db.sql.StatementUtils.attemptClose(StatementUtils.java:38)
at com.mchange.v2.c3p0.stmt.GooGooStatementCache$1.run(GooGooStatementCache.java:246)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:354)


or another error:

Could not complete transaction
org.hibernate.exception.GenericJDBCException: could not initialize a collection: [org.gridlab.gridsphere.portlet.impl.SportletData.Attributes#2c9f7d9706c8d8df0106c8da49b90027]
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
....
at java.lang.Thread.run(Thread.java:534)
Caused by: java.sql.SQLException: You can't operate on a closed connection!!!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:68)
... 70 more
Caused by: java.lang.NullPointerException
at org.postgresql.jdbc2.AbstractJdbc2Statement.close(AbstractJdbc2Statement.java:656)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.close(NewProxyPreparedStatement.java:1674)


Literally all I did was upgrade all hibernate 2 and co. jar files to hibernate 3. I find it strange that with hsql it all works but postgres now has problems accessing the database. Are there any possible flags that can be turned on either to solve the problem or to gain a better understanding why my app is now broken?

I just wish there was a hibernate.postgres.used=true flag or something...

Thanks, Jason

what should hibernate.postgres.used=true do ? Automagically remove possible bugs in postgresssql driver which for some reason has surfaced because you did a MAJOR version upgrade of hibernate ? sorry, but that is not possible at the moment (maybe in Hibernate 2010) - try updating the driver and if that does not work report it to the postgres guys.

I tried the latest postgres driver with no success-- however, based on the exceptions I reported, I have no way of knowing if this is in fact a postgres problem, a hibernate issue, or something with my own code. I'm happy to start digging but I don't know where...

Thanks, Jason

It looks like pool closes statement after connection was closed. Try to drop this pool.

Hi,

I had these entries in my props file:

###########################
### C3P0 Connection Pool###
###########################

hibernate.c3p0.max_size 10
hibernate.c3p0.min_size 2
hibernate.c3p0.timeout 5000
hibernate.c3p0.max_statements 100
hibernate.c3p0.idle_test_period 3000
hibernate.c3p0.acquire_increment 2
hibernate.jdbc.batch_size 0


You think I should comment out these lines?

Thanks, Jason

I'm using postgres and Hibernate 3. I just went through the transition and didn't have problems like this. Can you post some more information and I'll try to help?

If you could get it nailed down to a mapping file and a query that are causing you the problem I'll try to reproduce it over here.

Phill

As I understand from stack trace "com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.close" is called after connection was closed. There is a bug in application,hibernate or in pool, I do not see it stack trace . Just try to debug it without pool or try to change pool implementation, it will help to find this bug.

You might want to upgrade your copy of the c3p0 pool library. It could be a pool issue and there where some bugs in c3p0 related to statement closing at the wrong time.