[Zope-DB] How to do analysis? (was Re: Saga continues...)

[Dieter Maurer]

Chris Withers wrote at 2003-10-22 22:42 +0100:
 > Dieter Maurer wrote:
 > 
 > > I am quite happy with the current architecture (apart from the
 > > automatic connection in "__setstate__" which I have removed in our
 > > Zope version).
 > 
 > Hmm, so if one of your DA objects gets removed from the ZODB cache, how does the 
 > connection get re-opened?

The standard way is to get the connection via "DA()".
This call can create the connection when there is currently none.

I had to patch a few places in ZPsycopgDA (the only DA we
have in widespread use) such that they get the connection
via "DA()" rather than use it directly. But, it was at most
two places.

 > > The only bad thing I can see is that a few more connections
 > > are opened than are strictly necessary.
 > > This is only a problem when you have lots of DA instances
 > > lying around (while you need only one per database).
 > 
 > What if you're accessing LOTS of different databases?

If you access hundreds of different databases, this
can become a problem. But, in this case, you will
have a tough time even with a different architecture
(as file descriptors become the bottleneck).

 > These extra connections are something I'm really looking to get rid of...

When you like...


Dieter