If something goes wrong after content is indexed, the index is restored to its previous condition. This also means that Undo will restore an index to its previous condition. Finally, a ZCatalog can be altered privately in a Version, meaning no one else can see the changes to the index. Thus, only the part of the index that is needed is loaded into memory. Alternatively, an un-needed part of the index can be removed from memory.
Results are lazy .
A search that returns a tremendous number of matches won't return a large result set. Only the part of the results, such as the second batch of twenty, are returned. The ZCatalog is a free, Open Source part of the Zope software repository and thus is covered under the same license as Zope. It is being developed in conjunction with the Zope Portal Toolkit effort. Installing ZCatalog ZCatalog can be downloaded from the Zope download area and is also a module in the public CVS for Zope.