[ckan-dev] no autoflush in sqlalchemy

Mon Jan 17 15:07:06 UTC 2011

It seems to me a code simplification with a marginal performance cost
- I'm in favour. Anyone else have a view?

David

On 17 January 2011 14:36, David Raznick <david.raznick at okfn.org> wrote:
> Hello
>
> I propose we remove autoflush by default in ckan.  It caused a lot of bugs
> on the version upgrade due to its magical behavior.
>
> I have a patch in https://bitbucket.org/kindly/ckan/    on branch
> feature_switch_autoflush_off_by_default.
>
> This change simplifies code.  It only took 7 extra flushes/commits to make
> work and there are over 40 instances that we remove autoflush, so as not to
> cause error (I have not removed them in the patch yet).
>
> Things to know about using flush:
>
> * Most of the time nothing will change.   A commit implies flush.
> * You only need to flush if you expect a query to return an object you just
> saved.    i.e  if you  session.add(obj)  and you expect obj to be in a
> session.query.
> * A flush is handy when you want to get the primary key out before you do a
> commit.  i.e   session.add(obj);  session.flush();  obj.id  is now
> generated.
> * You can use them as a limited form of nested transaction.
>
> I do not see any downsides.
>
> Thanks
>
> David
>
>
>
>
>
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