[ZODB-Dev] Quick ZODB connection synch question

[Nicholas Henke]

On Mon, 2003-09-29 at 10:01, Shane Hathaway wrote:
> 
> Let's say you have connection A and connection B.  (It doesn't matter 
> whether A and B are in the same process or on different continents.) 
> Imagine you do the following with connection A:
> 
>  >>> A.root()["Test"] = 1
>  >>> get_transaction().commit()
> 
> Connection B will not see this change until it commits a transaction or 
> calls sync().  Here is what you should expect:
> 
>  >>> B.root()["Test"]
> KeyError: 'Test'
>  >>> B.sync()
>  >>> B.root()["Test"]
> 1
> 
> Furthermore, you should not expect B to be updated implicitly at 
> transaction boundaries unless some object in B actually got changed.
> 
> Now, Zope uses a little trick that avoids the need to calling sync(): it 
> opens a database connection for every HTTP request.  The only pitfall of 
> this trick is that if you don't also run an asyncore loop with ZEO, the 
> database will not receive ZEO invalidations.  You'll only fall into this 
> if you're using ZEO, you're not using sync(), and you're not using an 
> asyncore loop.

Thanks Shane~~
	I think I understand that -- but what I was asking for was a code
example setting up the use of the asyncore mainloop, or at least have
that example put more concretely into the 'Introduction to ZODB & ZEO'
guide linked from the main page for ZODB. It would help those new to
using ZEO, as the current ayncore info is just a small blurb kinda
hidden in the documentation.

Sorry for being such a pain~
Nic
-- 
Nicholas Henke
Penguin Herder & Linux Cluster System Programmer
Liniac Project - Univ. of Pennsylvania