Someone posted a docs suggestion to -devel, which made me look at the current sqlalchemy scaffold.
I'm not sure it's 'correct' a few weeks ago I asked Mike Bayer (sqlalchemy) what the best practices for webapps were ( https://groups.google.com/forum/#!topic/sqlalchemy/ZsHxDzlATCQ ) he responded with two links: fairly recently i wrote up as much as I could come up with on this, which > you can see first in the Session FAQ: > > http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html#session-frequently-asked-questions > > > and then regarding scoped_session in: > > http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html#using-thread-local-scope-with-web-applications > the big thing that i'm picking up off the current scaffold, is that there's a single scoped_session as DBSession in models.py ( https://github.com/Pylons/pyramid/blob/master/pyramid/scaffolds/alchemy/%2Bpackage%2B/models.py_tmpl ) , while the views.py uses that same session ( https://github.com/Pylons/pyramid/blob/master/pyramid/scaffolds/alchemy/%2Bpackage%2B/views.py_tmpl ) the scaffold seems to not invalidate the local sqlalchemy session , or suggest that a new one is created. It's my understanding that a few things should happen instead ( which are basically covered in the cookbook ) a) if a 'global' `DBSession` is used within a view, is should be explicitly instantiated to create a new thread/request local instance `DBSession()` and/or b) you could opt to be even more explicit and use tween to prep the session ( or use add_request_property ) -- but that setup action should also run a add_finished_callback to `remove` (invalidate) the session after the request. in pseudocode , something like.... def ScopedSession_cleanup(request): request.ScopedSession.remove() def tween_factory(handler, registry): def tween(request): request.ScopedSession = ScopedSession() request.add_finished_callback(ScopedSession_cleanup) return tween getting to the nuts and bolts: 1- http://docs.pylonsproject.org/projects/pyramid_cookbook/en/latest/database/sqlalchemy.html#using-a-non-global-session "def cleanup():" would be better to have `session.remove()`, not `session.close()` 2- https://github.com/Pylons/pyramid/blob/master/pyramid/scaffolds/alchemy/%2Bpackage%2B/views.py_tmpl bad : "one = DBSession.query(" better : "local_session = DBSession()" "local_session.query(" it might also make sense to replace `DBSession` with `DBSessionFactory`. thoughts ? -- You received this message because you are subscribed to the Google Groups "pylons-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to pylons-devel+unsubscr...@googlegroups.com. To post to this group, send email to pylons-devel@googlegroups.com. Visit this group at http://groups.google.com/group/pylons-devel. For more options, visit https://groups.google.com/groups/opt_out.
