[ckan-dev] no autoflush in sqlalchemy

Mon Jan 17 15:14:11 UTC 2011

Massively in favour.  The autoflush behaviour leads to unpredictable
results that are mysterious and hard to debug.  I'd say I lost 2 days
in my testing stuff as a result.  Of course, now I know about it it
would cost me less time, but others might have the same issues in
future.

Seb

On 17 January 2011 15:07, David Read <david.read at okfn.org> wrote:
> 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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>>
>>
>
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