[ZODB-Dev] what's the latest on zodb/zeo+memcached?

[Jim Fulton]

On Thu, Jan 17, 2013 at 12:31 PM, Claudiu Saftoiu <csaftoiu at gmail.com> wrote:
...
> One potential thing is this: after a zeopack the index database .fs file is
> about 400 megabytes, so I figure a cache of 3000 megabytes should more than
> cover it. Before a zeopack, though - I do one every 3 hours - the file grows
> to 7.6 gigabytes.

In scanning over this thread while writing my last message, I noticed
this.

This is a ridiculous amount of churn. There is likely something
seriously out of whack with your application.  Every application is
different, but we typically see *weekly* packs reduce database size by
at most 50%.

> Shouldn't the relevant objects - the entire set of latest
> versions of the objects - be the ones in the cache, thus it doesn't matter
> that the .fs file is 7.6gb as the actual used bits of it are only 400mb or
> so?

Every object update invalidates cached versions of the obejct in all
caches except the writer's.  (Even the writer's cached value is
invalidated of conflict-resolution was performed.)

> Another question is, does zeopacking destroy the cache?

No, but lots of writing does.

> If so then that
> would make sense. I'll have to preload upon every zeopack. If it's not that,
> then I'm not sure what it could be.

I think you have some basic application design problem(s).

Jim

-- 
Jim Fulton
http://www.linkedin.com/in/jimfulton
Jerky is better than bacon! http://zo.pe/Kqm