RE: [Zope] Re: Zope and mod_python
mmmm... I thought that thre was one cache per connection to Zeo ?? A standard Zope instance with Zeo has 4 connections to Zeo, and when you look at the cache status, it is different for each connection (different number of objects). So I am not sure that there is anything shared accross connections. If I am right, then it makes no real difference to have many Zope with one connection to Zeo vs. one Zope with many connections to Zeo. If I am wrong, then I agree, "it's a shame" :) Pascal -----Message d'origine----- De : Chris Withers [mailto:chris@simplistix.co.uk] Envoyé : jeudi 10 février 2005 11:36 À : Pascal Peregrina Cc : Tres Seaver; Zope Mailing List Objet : Re: [Zope] Re: Zope and mod_python Pascal Peregrina wrote:
I am not sure we can share anything between instances. I mean, each instance runs in a completely separate process.
That's a shame, 'cos ZEO client cache's can sometimes need ot be pretty huge, and, IIRC, in normal Zope, you only need one for all your threads.... Chris -- Simplistix - Content Management, Zope & Python Consulting - http://www.simplistix.co.uk ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com **********************************************************************
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Pascal Peregrina wrote: | mmmm... I thought that thre was one cache per connection to Zeo ?? | | A standard Zope instance with Zeo has 4 connections to Zeo, and when you | look at the cache status, it is different for each connection (different | number of objects). | So I am not sure that there is anything shared accross connections. There are two caches in play here: the in-memory cache is per-connection (and not specific to ZEO); the on-disk cache (which is ZEO-specific) is shared across connections. | If I am right, then it makes no real difference to have many Zope with one | connection to Zeo vs. one Zope with many connections to Zeo. | | If I am wrong, then I agree, "it's a shame" :) We would need to test to see if it ended up mattering. Cache behavior is almost *never* what I expect. Tres. - -- =============================================================== Tres Seaver tseaver@zope.com Zope Corporation "Zope Dealers" http://www.zope.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFCC5+2GqWXf00rNCgRAu1PAJ9dH0MvXl3+diqQwgMlToLF+oMTTwCfUycF swMKqa8LBjA+3iZG/1lzkLk= =57k+ -----END PGP SIGNATURE-----
Tres Seaver <tseaver@zope.com> wrote:
Pascal Peregrina wrote: | mmmm... I thought that thre was one cache per connection to Zeo ?? | | A standard Zope instance with Zeo has 4 connections to Zeo, and when you | look at the cache status, it is different for each connection (different | number of objects). | So I am not sure that there is anything shared accross connections.
There are two caches in play here: the in-memory cache is per-connection (and not specific to ZEO); the on-disk cache (which is ZEO-specific) is shared across connections.
| If I am right, then it makes no real difference to have many Zope with one | connection to Zeo vs. one Zope with many connections to Zeo. | | If I am wrong, then I agree, "it's a shame" :)
We would need to test to see if it ended up mattering. Cache behavior is almost *never* what I expect.
If ZEO cache became a problem, we could add a fake local ZEO server that caches and relays to the real ZEO server on a remote machine. Has anyone thought about or written such a beast ? Florent -- Florent Guillaume, Nuxeo (Paris, France) CTO, Director of R&D +33 1 40 33 71 59 http://nuxeo.com fg@nuxeo.com
Pascal Peregrina wrote at 2005-2-10 11:45 +0100:
A standard Zope instance with Zeo has 4 connections to Zeo
This is a misconception. A standard Zope instance has 4 ZODB connections but they all share a single (TCP) connection to ZEO -- and a single ZEO client cache. A ZODB connection has its onw independent ZODB cache. It is not shared with other ZODB connections. -- Dieter
participants (4)
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Dieter Maurer -
Florent Guillaume -
Pascal Peregrina -
Tres Seaver