[ZODB-Dev] Re:Perennity of ZODB format - Thanks
Pierre-Yves Delens
py.delens at lienterfaces.be
Sun Sep 26 03:41:58 EDT 2004
Thanks to all of you for nswers on 'Perennity of ZODB format'
PY Delens
----- Original Message -----
From: <zodb-dev-request at zope.org>
To: <zodb-dev at zope.org>
Sent: Saturday, September 25, 2004 6:00 PM
Subject: ZODB-Dev Digest, Vol 18, Issue 28
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| Today's Topics:
|
| 1. RE: How do I shut down of ZEO server with a HTTP request
| (Gfeller Martin)
| 2. Re: ZODB growing / What triggers a transaction? (Ge?ndert von
| jdb30570 at gmx.net) (Dieter Maurer)
| 3. Re: Perennity of ZODB format (Dieter Maurer)
| 4. Re: Perennity of ZODB format (Paul Winkler)
| 5. Re: Perennity of ZODB format (Jim Fulton)
|
|
| ----------------------------------------------------------------------
|
| Message: 1
| Date: Fri, 24 Sep 2004 18:00:40 +0200
| From: "Gfeller Martin" <Martin.Gfeller at comit.ch>
| Subject: RE: [ZODB-Dev] How do I shut down of ZEO server with a HTTP
| request
| To: <jim at zope.com>, <zodb-dev at zope.org>
| Message-ID:
| <B7824E219C630A4BB5F97190F523C12B635FA7 at vulcanos.ch.comitgroup.net>
| Content-Type: text/plain; charset="us-ascii"
|
| Thank you, Jim. I will enter a feature request.
|
| I think there is *no way* of properly shutting down a ZEO server under
| Windows, i.e., with giving it a chance to cleanup.
|
| I also want to be able to run and stop it as a normal process, not just
| when it is a service.
|
| Best regards,
| Martin
|
|
|
|
|
| -----Original Message-----
| From: Jim Fulton [mailto:jim at zope.com]
| Sent: Thursday, 23 Sep 2004 15:53
| To: Gfeller Martin
| Cc: zodb-dev at zope.org
| Subject: Re: [ZODB-Dev] How do I shut down of ZEO server with a HTTP
| request
|
|
| Gfeller Martin wrote:
| > Dear all
| >
| > is there a way to stop a ZEO Server with a HTTP request, in a similar
| way to shutting down a Zope Server over the control panel?
|
| Nope.
|
| > As I'm running on Windows, sending signals is not trivial.
|
| Obviously, It would be nice to run ZEO as a service.
|
| Perhaps you should submit a feature request to the ZODB bug tracker.
|
| Jim
|
| --
| Jim Fulton mailto:jim at zope.com Python Powered!
| CTO (540) 361-1714 http://www.python.org
| Zope Corporation http://www.zope.com http://www.zope.org
|
|
|
| ------------------------------
|
| Message: 2
| Date: Fri, 24 Sep 2004 21:06:59 +0200
| From: Dieter Maurer <dieter at handshake.de>
| Subject: Re: [ZODB-Dev] ZODB growing / What triggers a transaction?
| (Ge?ndert von jdb30570 at gmx.net)
| To: "jdb30570 at gmx.net" <jdb30570 at gmx.net>
| Cc: zodb-dev at zope.org
| Message-ID: <16724.28755.547681.857832 at gargle.gargle.HOWL>
| Content-Type: text/plain; charset=us-ascii
|
| jdb30570 at gmx.net wrote at 2004-9-21 22:48 +0200:
| > ...
| >The problem is: I have custom file and container classes derived from
| >File and Folder.
|
| I posted extensions to "fsdump" that shows you the size of the
| individual objects in a transactions.
| This allows you to find out which objects are responsible
| for the excessive growth.
|
| > ...
| >Each of these inherits from a class called 'UserAware'
| >which implements user specific features, such as a list of recently
| >visited items.
|
| Keep such information in separate persistent subobjects!
| Ensure that these subobjects remain small.
| Good candidates are "BTree" derivatives.
| Make a change to such an object only when something really changes.
|
| --
| Dieter
|
|
| ------------------------------
|
| Message: 3
| Date: Fri, 24 Sep 2004 21:54:23 +0200
| From: Dieter Maurer <dieter at handshake.de>
| Subject: Re: [ZODB-Dev] Perennity of ZODB format
| To: "Pierre-Yves Delens" <py.delens at lienterfaces.be>
| Cc: zodb-dev at zope.org
| Message-ID: <16724.31599.892899.318921 at gargle.gargle.HOWL>
| Content-Type: text/plain; charset=us-ascii
|
| Pierre-Yves Delens wrote at 2004-9-24 08:51 +0200:
| > ...
| >> Q.1 Do you have docs about the ZODB datas-format :
|
| The ZODB stores Python objects as (Python) pickles.
| Python tries hard to keep the pickle format compatible
| (such that newer version can still understand older pickles).
| I think, that up to now, there has not been a compatibility problem.
|
| How a storage manages the pickles (more precisely, the OID to pickle
| (and additional info) map) is decided by the storage.
| At the start of the "FileStorage" implementation is the desciption
| for the formats used by "FileStorage".
|
| > ...
| >differences between
| >ZODB releases, good practices, roadmap, or whatever ?
|
| This sounds a bit confusing...
|
| >> Q.2 I Will store datas partially in XML, or at least have to serialize
and
| >tranform to XML.
|
| Usually not -- because XML is a quite expensive serialization format.
|
| Zope provides the feature to export ZODB objects in an XML format.
|
| But, don't be fooled: the fact that something is XML serializable
| does not mean that it is easier to reconstruct that when a
| different (more efficient) serialization format is used.
|
| > >>> Among the vast choice of Python tools for XML, do you know about
best
| >choices for working in ZODB ?
|
| The ZODB is completely unconcerned which XML processing tools
| you use for your application.
|
|
| The Zope XML import uses "pyexpat" to parse the XML.
|
| --
| Dieter
|
|
| ------------------------------
|
| Message: 4
| Date: Fri, 24 Sep 2004 16:41:55 -0400
| From: Paul Winkler <pw_lists at slinkp.com>
| Subject: Re: [ZODB-Dev] Perennity of ZODB format
| To: zodb-dev at zope.org
| Message-ID: <20040924204155.GC3270 at slinkp.com>
| Content-Type: text/plain; charset=us-ascii
|
| On Fri, Sep 24, 2004 at 09:54:23PM +0200, Dieter Maurer wrote:
| > Pierre-Yves Delens wrote at 2004-9-24 08:51 +0200:
| > > ...
| > >> Q.1 Do you have docs about the ZODB datas-format :
| >
| > The ZODB stores Python objects as (Python) pickles.
|
| Isn't that up to the storage?
| Sure, most of the storages in use (FileStorage, DirectoryStorage)
| use pickles but that's not mandatory - see APE.
| Or maybe I misunderstood and the data first gets pickled before
| APE decides what to do with it? That seems wasteful. <shrug>
|
| More to the point, the ZODB serialization format is typically something
| that the user doesn't care about at all. Objects go in,
| objects come out, it "just works".
|
| --
|
| Paul Winkler
| http://www.slinkp.com
|
|
| ------------------------------
|
| Message: 5
| Date: Sat, 25 Sep 2004 09:14:31 -0400
| From: Jim Fulton <jim at zope.com>
| Subject: Re: [ZODB-Dev] Perennity of ZODB format
| To: Paul Winkler <pw_lists at slinkp.com>
| Cc: zodb-dev at zope.org
| Message-ID: <41556F37.1040106 at zope.com>
| Content-Type: text/plain; charset=us-ascii; format=flowed
|
| Paul Winkler wrote:
| > On Fri, Sep 24, 2004 at 09:54:23PM +0200, Dieter Maurer wrote:
| >
| >>Pierre-Yves Delens wrote at 2004-9-24 08:51 +0200:
| >>
| >>>...
| >>>
| >>>>Q.1 Do you have docs about the ZODB datas-format :
| >>
| >>The ZODB stores Python objects as (Python) pickles.
| >
| >
| > Isn't that up to the storage?
|
| No.
|
| > Sure, most of the storages in use (FileStorage, DirectoryStorage)
| > use pickles but that's not mandatory - see APE.
| > Or maybe I misunderstood and the data first gets pickled before
| > APE decides what to do with it?
|
| As originally designed, storage API theoretically deals with
| opaque strings. The storages aren't supposed to care what's in the
| strings. In practice, the strings are pickles and some storages,
| like the Berkeley storage and APE rely on this. The storage API
| should really be revised to reflect some sort of pickle explanation.
|
| > That seems wasteful. <shrug>
|
| It is the job of the database to do serialization. There are
| lots of details of serialization that storages should not be rsponsible
| for. APE is unusual becase it reserializes the data. Note that, thanks
| to cPickle, the upsteam serialization is quite fast.
|
| > More to the point, the ZODB serialization format is typically something
| > that the user doesn't care about at all. Objects go in,
| > objects come out, it "just works".
|
| Sure, at the application level, but it *is* an open documented format.
|
| Jim
|
| --
| Jim Fulton mailto:jim at zope.com Python Powered!
| CTO (540) 361-1714 http://www.python.org
| Zope Corporation http://www.zope.com http://www.zope.org
|
|
|
| ------------------------------
|
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