[Zope-dev] zope.sqlalchemy: Decoupling Zope3 and SQLAlchemy commit - how? Should I?

[Laurence Rowe]

This depends on whether you have other resources involved in the
transaction or not. I would assume that you will only have the sql
database committing in the transaction, in which case it makes not a
blind bit of difference if you commit separately or not - just make
sure each individual task is a separate item in the queue and ensure
your queue processor can retry failures.

Laurence

2008/11/2 Hermann Himmelbauer <dusty at qwer.tk>:
> Hi,
> In one of my Zope3 projects, I use lovely.remotetask to run specific tasks in
> background. These tasks do lengthy database operations via zope.sqlalchemy.
> Currently, lovely.remotetask seems to do a Zope3 commit() at the end of the
> task, which also does the SQLAlchemy commit.
>
> However, some tasks consist of a loop over self-contained operations,
> therefore it would be handy to commit after each such operation. This way, if
> one of the operations fail (e.g. due to some database error, such as locking,
> refrential integrity violation etc.), not the whole task is rolled back but
> only one operation. Moreover, the probability of database locks is reduced.
>
> But, how would I do that? First of all, I'd have to catch all database error,
> so that lovely.remotetask does not do a rollback on its own (which errors
> would that be?). Then I'd have to somehow commit - should I simply do a Zope3
> commit? Or should I somehow do a database commit via zope.sqlalchemy?
>
> Best Regards,
> Hermann
>
> --
> hermann at qwer.tk
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