[Cross-Posting from ServerFault]

I am in a development environment, and our test Oracle 9i server has been misbehaving for a few days now. What happens is that we have our JDBC connections disconnecting after a few successful connections.

We got this box set up by our IT department and handed over to. It is 'our problem', so options like 'ask you DBA' isn't going to help me. :(

Our server is set up with 3 plain databases (one is the main dev db, the other is the 'experimental' dev db). We use the Oracle 10 ojdbc14.jar thin JDBC driver (because of some bug in the version 9 of the driver). We're using Hibernate to talk to the DB.

The only thing that I can see that changed is that we now have more users connecting to the server. Instead of one developer, we now have 3. With the Hibernate connection pools, I'm thinking that maybe we're hitting some limit?

Anyone has any idea what's going on?

Here's the stack trace on the client:

Caused by: org.hibernate.exception.GenericJDBCException: could not execute query
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126) [hibernate3.jar:na]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114) [hibernate3.jar:na]
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) [hibernate3.jar:na]
at org.hibernate.loader.Loader.doList(Loader.java:2235) [hibernate3.jar:na]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129) [hibernate3.jar:na]
at org.hibernate.loader.Loader.list(Loader.java:2124) [hibernate3.jar:na]
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401) [hibernate3.jar:na]
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363) [hibernate3.jar:na]
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) [hibernate3.jar:na]
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149) [hibernate3.jar:na]
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) [hibernate3.jar:na]
...
Caused by: java.sql.SQLException: Io exception: Connection reset
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:829) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1049) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:854) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1154) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3370) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3415) [ojdbc14.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208) [hibernate3.jar:na]
at org.hibernate.loader.Loader.getResultSet(Loader.java:1812) [hibernate3.jar:na]
at org.hibernate.loader.Loader.doQuery(Loader.java:697) [hibernate3.jar:na]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259) [hibernate3.jar:na]
at org.hibernate.loader.Loader.doList(Loader.java:2232) [hibernate3.jar:na]