Re: [sqlalchemy] notin_ passed empty sequence with unexpected substitution
On Aug 6, 2013, at 8:14 PM, Victor Reichert vfr...@gmail.com wrote: Hi, I'm running: selected_eventids = [] selected_event = self.session.query(Master_Simulation_Event).filter(Master_Simulation_Event.cumulative_probability = selection_percentile, Master_Simulation_Event.event_id.notin_(selected_eventids) ).\ order_by(Master_Simulation_Event.cumulative_probability - selection_percentile).first() And it generates: 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine SELECT TOP 1 master_simulation_events.id AS master_simulation_events_id, master_simulation_events.event_id AS master_simulation_events_event_id, master_simulation_events.rate AS master_simulation_events_rate, master_simulation_events.sample_probability AS master_simulation_events_sample_probability, master_simulation_events.cumulative_probability AS master_simulation_events_cumulative_probability FROM master_simulation_events WHERE master_simulation_events.cumulative_probability = ? AND master_simulation_events.event_id != master_simulation_events.event_id ORDER BY master_simulation_events.cumulative_probability - ? 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine (0.19528160149168805, 0.19528160149168805) The important part is the notin_([]) is translated to: master_simulation_events.event_id != master_simulation_events.event_id I recieve the following warning: C:\Python27\lib\site-packages\sqlalchemy\sql\expression.py:1982: SAWarning: The IN-predicate on master_simulation_events.event_id was invoked with an empty sequence. This results in a contradiction, which nonetheless can be expensive to evaluate. Consider alternative strategies for improved performance. return o[0](self, self.expr, op, *(other + o[1:]), **kwargs) While it doesn't make a lot of sense to pass an empty list to an in_ clause I think passing an emtpy list list to notin_ clause is OK and it shouldn't be replaced. fixed in 3302187fea0ffd431b980081e7bc483ea364da2b (0.8.3) and 34ef21909bd6ed3574e37c345ca9e (master). You don't really need notin in any case, just use ~col.in_([]) for now. signature.asc Description: Message signed with OpenPGP using GPGMail
[sqlalchemy] notin_ passed empty sequence with unexpected substitution
Hi, I'm running: selected_eventids = [] selected_event = self.session.query(Master_Simulation_Event).filter(Master_Simulation_Event.cumulative_probability = selection_percentile, Master_Simulation_Event.event_id.notin_(selected_eventids) ).\ order_by(Master_Simulation_Event.cumulative_probability - selection_percentile).first() And it generates: 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine SELECT TOP 1 master_simulation_events.id AS master_simulation_events_id, master_simulation_events.event_id AS master_simulation_events_event_id, master_simulation_events.rate AS master_simulation_events_rate, master_simulation_events.sample_probability AS master_simulation_events_sample_probability, master_simulation_events.cumulative_probability AS master_simulation_events_cumulative_probability FROM master_simulation_events WHERE master_simulation_events.cumulative_probability = ? AND master_simulation_events.event_id != master_simulation_events.event_id ORDER BY master_simulation_events.cumulative_probability - ? 2013-08-06 18:03:43,196 INFO sqlalchemy.engine.base.Engine (0.19528160149168805, 0.19528160149168805) The important part is the notin_([]) is translated to: master_simulation_events.event_id != master_simulation_events.event_id I recieve the following warning: C:\Python27\lib\site-packages\sqlalchemy\sql\expression.py:1982: SAWarning: The IN-predicate on master_simulation_events.event_id was invoked with an empty sequence. This results in a contradiction, which nonetheless can be expensive to evaluate. Consider alternative strategies for improved performance. return o[0](self, self.expr, op, *(other + o[1:]), **kwargs) While it doesn't make a lot of sense to pass an empty list to an in_ clause I think passing an emtpy list list to notin_ clause is OK and it shouldn't be replaced. Is this a bug? ~Victor -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
