[hibernate-issues] [Hibernate-JIRA] Closed: (HHH-1578) queries inside events - scenario which fails + fix

queries inside events - scenario which fails + fix --------------------------------------------------- Key: HHH-1578 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1578 Project: Hibernate Core Issue Type: Bug Components: core Affects Versions: 3.1.2 Reporter: Tomasz Bech Assignee: Steve Ebersole It is related to the forum topic: http://forum.hibernate.org/viewtopic.php?p=2294885#2294885. However I put full and better description below. preInsert event is used to make query on DB - to check some integrity. Following scenario fails: - insert object A; - insert object A'; (of type A, but different values than before) - commit; it gives stack trace: This gives exception: aused by: org.hibernate.exception.GenericJDBCException: could not insert: 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 org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2078) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2427) at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:51) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:243) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:227) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:140) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:296) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1009) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:356) at org.hibernate.transaction.CacheSynchronization.beforeCompletion(CacheSynchronization.java:59) at org.jboss.tm.TransactionImpl.doBeforeCompletion(TransactionImpl.java:1473) at org.jboss.tm.TransactionImpl.beforePrepare(TransactionImpl.java:1092) at org.jboss.tm.TransactionImpl.commit(TransactionImpl.java:306) ... 63 more Caused by: java.sql.SQLException: Connection handle has been closed and is unusable at org.jboss.resource.adapter.jdbc.WrappedConnection.checkStatus(WrappedConnection.java:526) at org.jboss.resource.adapter.jdbc.WrappedConnection.checkTransaction(WrappedConnection.java:513) at org.jboss.resource.adapter.jdbc.WrappedStatement.checkTransaction(WrappedStatement.java:537) at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:223) at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:23) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2062) ... 76 more Following scenario works fine: - insert object A - commit; Following scenario also works fine: - insert object A - insert object B - commit; I've spend a day to analyze the problem, as the preInsert+queries are crucial for our project. The order of operations is as follows: - prepareBatchStatement is called on AbstractBatcher; - my suplied query is executed; - prepareBatchStatement is called on AbstractBatcher; The problem appears because the 'batchUpdate' statement is reused in second call: public PreparedStatement prepareBatchStatement(String sql) throws SQLException, HibernateException { sql = getSQL( sql ); if ( !sql.equals(batchUpdateSQL) ) { batchUpdate=prepareStatement(sql); // calls executeBatch() batchUpdateSQL=sql; } else { log.debug("reusing prepared statement"); //here - REUSING prepare statement log(sql); } return batchUpdate; } and it is why insert A, preinsert-query, insert B scenario works, and insert A, preinsert-query, query A' doesn't. The query which was called just before the second insert of A' has closed its connection, but this connection belongs to batchUpdate too :(. The function responsible for tracking if the connection cen be closed is: public boolean hasOpenResources() { return resultSetsToClose.size() > 0 || statementsToClose.size() > 0 ; } It simply doesn't take into consideration that batchUpdate also has open connection - batchUpdate is not added to the statementsToClose also (as it is in the prepareQueryStatement). Golden patch would be to add batchUpdate to the statementsToClose map. But the same can be reach by (this is a fix): public boolean hasOpenResources() { return resultSetsToClose.size() > 0 || statementsToClose.size() > 0 || batchUpdate != null; } BatchUpdate when executed (in executeBatch) is closed and set to null = its connection can be released. I've tested the change, there is no side-effects (no leaked open connections) and the above scenario works. (in fact full execution order is: preInsert-query, insert A, preInsert--query, insert A', but the first preInsert-query works ok.)