Tim Peters wrote:
[Paul Winkler]

Heh. Well, I had a site that under some usage patterns would
occasionally slow to a crawl with cache flips every few minutes.  That
was with the old default 20 MB cache size.  I think I left it at
500 MB or so and that site's been fine since. But the performance
demands were pretty low.

Yes, 20MB is _very_ small.  It may have seemed conservatively safe 10
years ago when disks were much smaller, but now it's ludicrously

OTOH, the larger the ZEO cache file, the longer it may take startup or
reconnection cache verification to complete, so there's always some
reason not to do the obvious thing <0.3 wink>.

This is only a problem if:

1. a persistent cache is used or

2. the client gets disconnected from the server, without
   restarting, long enough for the server to commit enough
   transactions for the server to be able to do enough quick

We seem to have a lot of problems with persistent caches for
some reason, so I tend to recommend against their use.  I'm
not sure what's going on there.  I still find them useful in
situations in which the connection to the server is slow.

the second case should be rare.

I would definately error in the direction of using a
larger cache


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