Persistent objects

Paul Rubin http
Sun Dec 12 13:16:40 CET 2004


Duncan Booth <duncan.booth at invalid.invalid> writes:
> Have you looked at ZODB and ZEO? It does most of what you ask for,
> although not necessarily in the way you suggest.

You're the second person to mention these, so maybe I should check into
them more.  But I thought they were garden-variety persistent object
schemes that wrote pickles into disk files.  That's orders of magnitude
slower than what I had in mind.

> It doesn't attempt to hold everything in memory, but so long as most of 
> your objects are cache hits this shouldn't matter. Nor does it use shared 
> memory: using ZEO you can have a client server approach so you aren't 
> restricted to a single machine.

Well, if it doesn't use shared memory, what does it do instead?  If
every access has to go through the TCP stack, you're going to get
creamed speed-wise.  The mmap scheme should be able to do millions of
operations per second.  Are there any measurements of how many
ops/second you can get through ZODB?



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