I never did understand the pros or cons of running autocommit=True, aside from this flushing issue. Are there performance implications ?
On Mon, Feb 7, 2011 at 1:22 PM, Michael Bayer <mike...@zzzcomputing.com> wrote: > I actually just did a little bit of reverse course on this in 0.7. I've > moved all the accounting into the try/except block so that the flush > completes fully before the autocommit expires everything. This is a change > to a pattern that's been the same way since 0.4 so hoping nothing bad happens > when we put 0.7 out into betas. > > > On Feb 7, 2011, at 2:52 PM, Romy Maxwell wrote: > >> Are there any downsides to setting expire_on_commit=False when using >> autocommit=True ? In other words, should I expect to see stale data or >> other side effects ? >> >> On Mon, Feb 7, 2011 at 8:30 AM, Michael Bayer <mike...@zzzcomputing.com> >> wrote: >>> >>> On Feb 7, 2011, at 7:42 AM, Romy Maxwell wrote: >>> >>>> Hey Michael, >>>> >>>> I didn't wanna revive a really old thread >>>> [http://www.mail-archive.com/sqlalchemy@googlegroups.com/msg16598.html], >>>> so I figured maybe you won't mind the email. >>>> >>>> I don't understand why, in the thread, using autocommit=True makes the >>>> object unreachable, or what that actually means. I'm assuming it was >>>> referring to the latter part of the code: >>>> >>>>> o = s.query(T).get(2) >>>>> o.id = 10 >>>>> o.description = "Changed" >>>>> s.flush() >>>> >>>> With autocommit=True, I've always thought flushes created their own >>>> transactions, like so: >>>> >>>> s.begin() >>>> s.flush() >>>> s.commit() >>>> >>>> But if that was true, then the commit happens after the flush. How >>>> would the commit expire anything and/or make anything unreachable for >>>> the flush ? >>> >>> >>> The commit is expiring because that's what it does when expire_on_commit is >>> True. So the flush goes into its post-commit accounting, it in fact has >>> to reload all the objects, one at a time, so is hugely inefficient and I'm >>> going to add a big warning for that in 0.7, ticket 2041. >>> >>> >>> > > -- 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.
