On Nov 2, 2010, at 11:46 PM, Warwick Prince wrote: > Hi Michael > > I have an issue I can't fathom regarding Pools. I'm doing testing and hit > the following error at exatly the same point each time; > > File "C:\Documents and Settings\wprince\Desktop\PY CODE > DEVELOPMENT\pyDAP\DAPForm.py", line 3805, in _processQuery > self._queryCount = self._query.count() > File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1888, in > count > should_nest = should_nest[0] > File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1924, in > _col_aggregate > mapper=self._mapper_zero()) > File "C:\Python26\lib\site-packages\sqlalchemy\orm\session.py", line 740, > in scalar > return self.execute(clause, params=params, mapper=mapper, **kw).scalar() > File "C:\Python26\lib\site-packages\sqlalchemy\orm\session.py", line 734, > in execute > return self._connection_for_bind(engine, close_with_result=True).execute( > TimeoutError: QueuePool limit of size 5 overflow 10 reached, connection timed > out, timeout 30 > > I'm creating a basic "create_engine" using defaults for the pool settings (as > you can tell). Within each Thread that does the connection, I create a new > engine, metadata and scoped session. That thread then does a basic query (in > this case NOT using a session at all, just a direct table query) and then I > do everything I can think of to close the connections. I do this; > > engine.dispose() > session.commit() > session.close() > > and then the class instance that holds all these is removed and the thread > terminates. All works fine (i.e. no errors or exceptions) until I reach the > 10 overflow limit and then it dies. Each destroy of an engine and recreate > of an engine is at least a second apart so it's not being thrashed at all. > > What am I missing?
The error is local to a single engine. So engine.dispose() has no impact on the issue. While a Session will maintain a single checked out connection, result sets that are returned by engine.execute(<some select>) and <some select>.execute() also do so, so be sure to fully exhaust and/or close() those result sets as well. > > Cheers > Warwick > > Warwick Prince > Managing Director > mobile: +61 411 026 992 > skype: warwickprince > > phone: +61 7 3102 3730 > fax: +61 7 3319 6734 > web: www.mushroomsys.com > > > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to sqlalch...@googlegroups.com. > To unsubscribe from this group, send email to > sqlalchemy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sqlalchemy?hl=en. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
