On Mon, Aug 3, 2009 at 11:09 PM, toutpt<tou...@gmail.com> wrote:
> I don't really understand why all these improvements are not merged
> inside plone3.X and CMF and are marked up as 'experimental'.

The opaque items issue at hand is not a simple and clear "bug fix". On
the Plone level we have decided to no longer support this particular
feature of CMF as it causes too much of a performance bottleneck for
us. This is removing a feature which might be used by custom code or
add-ons, even though there are no known add-ons, which actually depend
on this feature. In a major release like the new Plone 4, we can make
such a more radical change and remove a feature, but this has been too
invasive to put into a Plone 3.x release.

The improvements form the contentcreation package are similar and can
potentially cause problems for code that relies on specific semantics
during content creation in the portal_factory tool. The changes have
been merged into the Plone 4 code as well now, but have been found to
be too risky for Plone 3.x.

The catalogqueryplan work is of a different kind and really requires a
complete re-factoring of the catalog system as used in Plone to be
done properly. Right now it is a set of monkey-patches for various
internals of the catalog and the BTree classes. The work is also still
ongoing to make the code more general. Since the catalog is one of the
spots that thanks to its widespread use in Plone is also customized
extensively, changes to it are particular risky to do.

There is a whole number of other changes and techniques that are known
to speed up Plone. One of the major problems is that these are often
very easy to do given a particular single site, which can assume a lot
of constraints about the way it is used. But the complexity of
different usage patterns and the endless flexibility of configuration
options make it very hard to improve performance in a general way.

A typical issue of this kind is the question if a particular feature
needs to be configurable per database configuration or just based on
file system settings. In the latter case there can often be a number
of things that can be cached at startup time avoiding the additional
database lookups per view call. This is something Plone cannot do in
general, but can bring substantial improvements for particular sites.

Zope-CMF maillist  -  Zope-CMF@lists.zope.org

See https://bugs.launchpad.net/zope-cmf/ for bug reports and feature requests

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