Watch out: Python 2.4 ZEO client and Python 2.6 ZEO Server

Today was interesting when an issue with saving content on a Plone 3.3.5 site got reported to me. The system was producing undecipherable error messages about ZEO disconnections and database conflicts whenever someone would try and create some content within Plone (folders, particularly). Errors looked like:

Module ZEO.zrpc.connection, line 796, in wait. DisconnectedError" and "raise ReadConflictError().
ReadConflictError: database read conflict error"

and also:

ERROR ZEO.zrpc (2515) can't decode message: '(K\x11K\x01U\tserialnos(]((U\x08\x00\x00\x00\x00\x00X\x...'

— essentially the issue described here. My ZEO server was running ZODB3 3.9.5 …

in Plone · Mon 11 July 2011

Plone/Zope: Truncating a Data.fs back to a certain date/time

Okay. So, anyone out here who’s listening — particularly those overly-enthusiastic users — don’t try to recursively wget your Plone site (or other CMS, for that matter) whilst you’re logged in with an account that can make edits. It will lead to a very bad situation where your site administrator and technical team need to step in and fix your mistakes. For the uninitiated, a loose recursive wget (when logged in with some degree of Edit rights) will hit every link that’s on your pages, and I mean in the (X)HTML source. For a Plone site, this …

in Plone · Tue 20 July 2010

Plone 4: Local Zeo blobs conflict with Plone instance

As the title suggests, there’s a conflict between a Zeo database instance being run together with a Plone 4/Zope instance, and them trying to share the same blob storage folder.  But, this only happens if you misunderstand or incorrectly set the option of  shared-blob = off, and blob-storage to be the same location as for Zeo in your buildout. If that previous set of (seemingly jumbled) thoughts doesn’t make any sense to you, then move along, nothing to see here.

By default, at the time of writing, blob support within Zeo runs with the bushylayout, and creates …

in Plone · Tue 06 July 2010

Migrating a Plone site off to another database (Zeo)

Another of the interesting things in my professional life has been migrating a Plone site from one database (where it lived as a dev site, along with many others) onto a nice, clean database of its own.  Now, yes, I’m aware that the export/import feature of Zope isn’t supposed to be used for migrating content or sites.  I am also aware, however, through personal experience, that things have always been fine because I’m using the same eggs and essentially the same installations everywhere, thanks to buildout.

So, the process goes as follows, with the above-mentioned points …

in Plone · Wed 30 September 2009