Jorge Godoy wrote: > "Ben Sizer" <[EMAIL PROTECTED]> writes: > > > So that means that each request is handled sequentially... is that > > guaranteed by TurboGears? > > It isn't guaranteed by TG. I believe that if I started two transactions on > the DB, the second one starting before the first expires the visit. Thinking > about PostgreSQL that uses MVCC -- so this becomes database dependent -- then > I'd have two snapshots one with the visit expired and the second with the > visit still OK. > > For this specific second request it'd still be able to retrieve data from the > database, but a third transaction started right after the expiration has been > commited by the first transaction wouldn't be able to do it since in this new > snapshot the visit would have already expired. > > Adding to this there's also the isolation level from the database (it is > possible to serialize all transactions, it is possible to read uncommited > data, etc. -- it all depends on your database implementation of these > isolation levels). > > I dunno if I was clear here. If not, ask for more :-)
You were probably clear, but I don't know much about the detail of database transactions and so on. But even if I drop down to the database level and make the update directly, can I be sure that the correct values propagated up to SQLObject in the other threads? > > Ok... do you know how that ties in with the use of > > 'sqlobject.util.threadinglocal'? > > No. I haven't used threads with SO. And I'm holding myself on it, thinking > about doing new apps with SA... This all worries me... threads are surely a pretty fundamental part of many long-running process models, yet nobody except yourself is able to tell me what is safe and what is not. I at least need to know what sort of exceptions I need to be able to catch and which circumstances they may arise in, and which objects in the Turbogears system I can pass between Python threads and those which I can't. -- Ben Sizer --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TurboGears" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/turbogears?hl=en -~----------~----~----~----~------~----~------~--~---
