Re: Django, Postgres and recovering from database constraints

thanks,

I'll give it a try tomorrow and let you know.

Xavier.

Le 1 févr. 2011 à 19:57, Casey S. Greene a écrit :

> Also (sorry for the follow-up spam but I just remembered this) if you are hoping to use the database level autocommit (postgres 8.2 or later), you need to configure it:
>
> Autocommit mode
> New in Django 1.1: Please, see the release notes
>
> If your application is particularly read-heavy and doesn't make many database writes, the overhead of a constantly open transaction can sometimes be noticeable. For those situations, if you're using the postgresql_psycopg2 backend, you can configure Django to use "autocommit" behavior for the connection, meaning that each database operation will normally be in its own transaction, rather than having the transaction extend over multiple operations. In this case, you can still manually start a transaction if you're doing something that requires consistency across multiple database operations. The autocommit behavior is enabled by setting the autocommit key in the OPTIONS part of your database configuration in DATABASES:
>
> 'OPTIONS': {
> 'autocommit': True,
> }
>
> from
> http://docs.djangoproject.com/en/1.2/ref/databases/
> --
> Casey
>
> On 02/01/2011 01:52 PM, Casey S. Greene wrote:
>> Here is some code pulled from my (using postgres) django application
>> that recovers fine. Perhaps this is helpful to you. I am storing the
>> non-unique values and dealing with them later (pulling from an external
>> source that is supposed to have unique IDs assigned but they don't
>> always pan out somehow...).
>>
>> from django.db import IntegrityError, transaction
>>
>> #Other Code
>> ...
>> #relevant code
>> try:
>> sid = transaction.savepoint()
>> foo = FooModel(fooarg=fooarg, ...)
>> foo.save()
>> except IntegrityError:
>> transaction.savepoint_rollback(sid)
>> non_unique_foo.append((FooDB, FooID))
>>
>> Hope this helps!
>> Casey
>>
>> On 02/01/2011 11:48 AM, Xavier Ordoquy wrote:
>>>
>>> Le 1 févr. 2011 à 15:59, bruno desthuilliers wrote :
>>>> On 1 fév, 15:24, Xavier Ordoquy<xordo...@linovia.com> wrote:
>>>>> Hi all,
>>>>>
>>>>> I got a project which sometime outputs database integrity errors
>>>>> (key violates unique constraint).
>>>>> It is fine since I'm keeping an events table which may have several
>>>>> creation messages for the same object.
>>>>
>>>> Hmmm... Either I misunderstood you or you have a design problem here.
>>>
>>> You probably miss the big picture (ie, several legacy databases, each
>>> with their own models plus synchronization between them and a central
>>> django database).
>>>
>>>> But anyway:
>>>>
>>>>> Until now, I was just catching the exception and forgot about it.
>>>>>
>>>>> Today, I'm not sure this is the right way.
>>>>> If the exception in itself is correctly processed, I noticed that
>>>>> any database operation behind raises another exception saying that
>>>>> postgresql hates me and won't perform any other operation (current
>>>>> transation is aborted, commands ignored until end of transaction
>>>>> block.).
>>>>
>>>>> I already tried to end the transaction, but django will let me know
>>>>> I'm not within a transaction....
>>>>
>>>> Hu ?
>>>>
>>>> I assume you did read this:
>>>> http://docs.djangoproject.com/en/dev/topics/db/transactions
>>>>
>>>> and specially this part:
>>>> http://docs.djangoproject.com/en/dev/topics/db/transactions/#handling-exceptions-within-postgresql-transactions
>>>>
>>>
>>> Actually, I posted because this just doesn't seem to work.
>>> If I try to rollback the transaction, I just get a nice error that
>>> I'not within a transaction.
>>>
>>> I haven't tested savepoints, but transaction rollback and autocommit
>>> doesn't seem to work here.
>>> I'll probably write a sample project this week to point the issue.
>>>
>>> Regards,
>>> Xavier.
>>>
>
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