[Zope-DB] RFC: mxODBCZopeDA & ZEO
charlie at egenix.com
Wed May 26 13:39:57 EDT 2004
On 2004-05-25 at 18:38:19 [+0200], Chris Withers <chris at simplistix.co.uk>
> Network shares, Subversion, etc...
> Myself? I setup a whole instance in Subversion and check it out onto any
> I want a client one...
Interesting. I assume this involves using some kind of file storage?
> >>>3) heterogeneous clients may in some circumstances confuse each other
> > take the mxODBCZopeDA for example: if a connection is configured to talk
> > to
> > DSN=Chris or use a specific driver then this may not on all clients.
> Ooo... ouch, yeah. Sounds like a system architecture problem. This is part
> cluster "being hard". Generally, having homogeneous nodes in a cluster is
> way to go, in which case the situation you describe shouldn't apply...
Yes, wasn't possible in the test configuration but maybe useful for support
enquiries. Non-heterogeneous clients are likely to cause problems in
> > This is an RFC targetted at those with real-life ZEO installations with
> > RDBMS. The example you cite is one where I think it might make more sense
> > to
> > have a single connection
> explain what you mean by connection.
>From website to cluster. The current state sets up identical copies of the
connection object in the various ZEO clients. They have to communicate
through a local ODBC manager with the database. In a sense this goes against
something like the mxODBCZopeDA which should be able to handle all necessary
connections from all ZEO clients in a single object. This looks like it's
going to remain a theoretical difference as there is unlikely to be any
performance difference either way.
We're essentially looking at the question: what does ZEO give you and how
does it work?
However, it looks like the common setup avoids the pitfalls of separate
> > talking to several clients which do the rendering.
> explain what you mean by client.
> > But we don't really know how much ZEO is out there and how much of it uses
> > Zope-DAs. We know that the mxODBCZopeDA works with ZEO but maybe it could
> > work better.
> explain what you mean by "works with zeo"
> And there's PLENTY of ZEO out there ;-)
That's good to hear. There doesn't seem to be much running with the
mxODBCZopeDA which seems to suggest that such sites primarily use the ZODB
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