Hello! I'm iterating over a session to look at all the objects: for obj in session: do_something_cool(obj)
Yesterday this caused what looks like a deadlock in SQLAlchemy code. Here is the stack I grabbed using gdb: 1. /python2.5/sqlalchemy/orm/session.py:1353 (Session.__iter__) 2. /python2.5/sqlalchemy/orm/identity.py:184 (WeakInstanceDict.values) 3. /python2.5/sqlalchemy/orm/identity.py:188 (WeakInstanceDict.itervalues ) ** self._remove_mutex.acquire() 4. /python2.5/sqlalchemy/orm/state.py:501 ( MutableAttrInstanceState.__resurrect) 5. /python2.5/sqlalchemy/orm/attributes.py:925 (Events.run) 6. /python2.5/sqlalchemy/orm/mapper.py:2424 (_event_on_resurrect) 7. /python2.5/sqlalchemy/util.py:953 (OrderedSet.__iter__) 8. /python2.5/sqlalchemy/orm/state.py:477 ( MutableAttrInstanceState._cleanup) 9. /python2.5/sqlalchemy/orm/identity.py:139A (WeakInstanceDict.remove)** self._remove_mutex.acquire () I'm running SQLAlchemy 0.6.5. Is this a known issue or am I doing something wrong? On a somewhat related note, am experiencing the issue where lots of objects in a session significantly reduces performance. It appears I am experiencing the penalty for using MutableTypes on objects described here: http://readthedocs.org/docs/sqlalchemy/en/latest/core/types.html#base-type-api. The doc states: In order to detect changes, the ORM must create a copy of the value when it is first accessed, so that changes to the current value can be compared against the “clean” database-loaded value. Additionally, when the ORM checks to see if any data requires flushing, it must scan through all instances in the session which are known to have “mutable” attributes and compare the current value of each one to its “clean” value. It doesn't seem like I should have to pay this penalty because with my type I actually know when any updates occur. The type just supports models.mutable_value.update(data). Is there a way to notify the model/session that the value has been updated when someone calls update, so the full scan of all instances is not needed? Do I need to rewrite the update function to translate models.mutable_value.update(data) to actually generate models.mutable_value = new_mutable_value or is there a better way to do this? Thanks for any help! -Lenza -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@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.
