Attention. There is no db.begin(). it is implicit. You can commit
automatically but why not:
while queue is not empty:
task = db(~status.belongs(('done','failed'))).select(limitby=
(0,1))[0]
success = do_long_thing(task)
if success:
task.update(status = 'done')
else:
task.update(status = 'failed')
On Dec 29, 2:10 pm, toomim <[email protected]> wrote:
> Very clever, thank you! If it crashes, these items will be lost
> though. Is there a way to use transactions, to pull a single item at
> a time from the table, process and delete it, within a single
> transaction? Something like this:
>
> while queue is not empty:
> db.begin()
> task = db(status != 'done').select(limitby=(0,1))[0]
> task.update(status = 'done')
> success = do_long_thing(task)
> if success:
> db.commit()
> else:
> db.rollback()
>
> This way if the code fires an exception, or the computer crashes, the
> database will roll back to its prior state automatically. The problem
> is there is no begin statement in web2py. All begin statements seem
> to be automatic. Is it possible to do one manually? Can I turn off
> the automatic one?
>
> On Dec 29, 12:04 am, Thadeus Burgess <[email protected]> wrote:
>
> > Ah yes, so back to my original thought
>
> > db(status == 'pending').update(status = 'pending-' + request.now)
>
> > for db(status == 'pending-' + request.now).select():
> > task.update_record(status = 'processing-' + request.now
> > success = do_the_long_thing(task)
> > fail
> > if success:
> > task.update_record(status = 'done')
>
> > -Thadeus
>
> > On Tue, Dec 29, 2009 at 1:52 AM, toomim <[email protected]> wrote:
> > > sk.update_record(status == 'proce
>
>
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