[ckan-dev] no autoflush in sqlalchemy

[David Raznick]

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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.okfn.org/pipermail/ckan-dev/attachments/20110117/78f05736/attachment.html>