ZODB performance (was Re: low-end persistence strategies?)

[Dave Brueck]

Chris Cioffi wrote:
> I'd like to second this one...ZODB is *extremely* easy to use.  I use
> it in projects with anything from a couple dozen simple objects all
> the way up to a moderately complex system with several hundred
> thousand stored custom objects.  (I would use it for very complex
> systems as well, but I'm not working on any right now...)

Chris (or anyone else), could you comment on ZODB's performance? I've Googled 
around a bit and haven't been able to find anything concrete, so I'm really 
curious to know how ZODB does with a few hundred thousand objects.

Specifically, what level of complexity do your ZODB queries/searches have? Any 
idea on how purely ad hoc searches perform? Obviously it will be affected by the 
nature of the objects, but any insight into ZODB's performance on large data 
sets would be helpful. What's the general ratio of reads to writes in your 
application?

I'm starting on a project in which we'll do completely dynamic (generated on the 
fly) queries into the database (mostly of the form of "from the set of all 
objects, give me all that have property A AND have property B AND property B's 
value is between 10 and 100, ..."). The objects themselves are fairly dynamic as 
well, so building it on top of an RDBMS will require many joins across property 
and value tables, so in the end there might not be any performance advantage in 
an RDBMS (and it would certainly be a lot work to use an object database - a 
huge portion of the work is in the object-relational layer).

Anyway, thanks for any info you can give me,
-Dave