.. contents::


Documentation
=============


Usage and goal
--------------

Add collective.catalogcleanup to the eggs in your buildout (and to zcml on
Plone 3.2 or earlier).  This makes a browser view available on the
Plone Site root: ``@@collective-catalogcleanup``.

This goes through the portal_catalog and removes all catalog brains
for which a ``getObject`` call does not work.  In other words, it
removes brains that no longer belong to an actual object in the site.

Similar cleanups are done for the uid_catalog and the
reference_catalog.

The goal is to get rid of outdated brains that could otherwise cause
problems, for example during an upgrade to Plone 4.

``@@collective-catalogcleanup`` by default does a dry run, so it
only reports problems.  Call it with
``@@collective-catalogcleanup?dry_run=false`` to perform the actual cleanup.


Details
-------

So what does the catalog cleanup do?

- It removes stuff!  You *must* make a backup first!

- It handles these catalogs: ``portal_catalog``, ``uid_catalog``,
  ``reference_catalog``.

- For each catalog it reports the number of catalog brains it
  contains.

- It removes brains that have a UID of ``None``.

- It removes brains of which the object is broken.  This can happen
  when the object belongs to a package that is no longer available in
  the Plone Site.

- It removes brains of which the object cannot be found.

- It looks for non unique uids.  There can be some legitimate reasons
  why some brains may have the same UID, for example when they belong
  to comments: the UID is inherited from the parent object.  Those
  items are kept.  For other items we accept one object and we give
  the other objects a new UID.

- References between objects that no longer exist or are broken, will
  be removed.

- A simple report will be printed in the browser.  For one catalog it
  may look like this::

    Handling catalog portal_catalog.
    Brains in portal_catalog: 20148
    portal_catalog: removed 25 brains without UID.
    portal_catalog: removed 100 brains with status broken.
    portal_catalog: removed 5 brains with status notfound.
    portal_catalog: 249 non unique uids found.
    portal_catalog: 249 items given new unique uids.

- The instance log may contain more info, about individual items.


Alternatives
------------

- A clear and rebuild of the portal_catalog should have partially the
  same effect, but it will likely take a lot longer and it will not
  solve some of the problems mentioned above.  But this is definitely
  the most logical thing to try before giving
  ``collective.catalogcleanup`` a go.


Compatibility
-------------

I have tried this on Plone 3.3 and 4.1.  It will likely work on other
versions as well.

I have not tried it with Dexterity items.  It might not be needed for
those.  Likely, it will either succeed normally or you get an
AttributeError somewhere and the cleanup run is aborted.


Authors
-------

Maurits van Rees
