----- Original Message ----- From: "Paul Browning" <paul.browning@bristol.ac.uk>

--On 28 February 2003 18:55 +0100 "M.-A. Lemburg" <mal@lemburg.com> wrote:

<List of features snipped>

Can someone who has a deeper understanding of this area than I please contrast (ideally against the mxODBC Zope DA feature list) things with ZOracleDA/DCOracle2?

The links from <http://www.egenix.com/> took me eventually to

<http://www.datadirect-technologies.com/products/odbc/ken-north-report.asp>

and the "Oracle ODBC Performance - Faster than Native" stuff.

...

From birth I've always been told ODBC is sloooowww .... don't go there. Might mxODBC Zope DA offer advantages to Zope/Oracle sites?

We've had a tortured history with Zope+Oracle+Solaris (cf. <http://www.zope.org/Members/glpb/solaris>) and are about to side-step this by going Zope+Oracle+Linux.

But the Oracle bit (i.e. ZOracleDA/DCOracle2) of the equation still looks dubious from time to time and so hence my questions.

well, I am no expert either but AFAIK Oracle uses SQL*NET for ODBC communications (ODBC sits on top of SQL*NET). Not sure if this is slower or not. I also have the impression that ODBC is slower per se, but perhaps coupled with better connection pooling it makes mxODBC faster? Nad how would mxODBC's pooling differ from Zope's "pooling" of connections by keping them open? I understand from previous mailexchange that the preformance of a heavly DB driven (DB=RDBMS) is in part defined by the amount of ZODB-connections as well as the amount of threads available to the Zope-process. I wonder though if the *sheer number* of active/connected ZOracleDA objects in the ZODB has some relevance to those numbers (ie. more open DA objects means increase threads and/or ZODB connections?). I have not read any specific numbers and I have yet to begin to understand how the amount of ZODB connections has an impact on the usage of ZOracleDA connections/objects. We do have experienced problems when using many connections to different schemas and I know that at least one more person has experienced similar problems (mem leaks, etc). Some of them wnet away as we reduced the amount of DA objects. Also, I would like to know how the kind of connection pooling that mxODBC uses benefits Zope. Does it spawn it's own threads in an external process or how does it work? Would it be possible to increase the performance of DCOracle2 by using similar tchniques? Thanks, /dario