Log message for revision 115682:
Provide some high level text about the catalog changes
--- Zope/trunk/doc/WHATSNEW.rst 2010-08-14 17:05:47 UTC (rev 115681)
+++ Zope/trunk/doc/WHATSNEW.rst 2010-08-14 18:20:40 UTC (rev 115682)
@@ -98,6 +98,31 @@
integration layer and make the Zope Toolkit a normal integral part of Zope 2.
+The ZCatalog and the default set of indexes as found in the PluginIndexes
+package have seen a large number of changes. Most of these have been pioneered
+in add-on packages in the Zope community over the last years and now have found
+their way back into the core. The largest change is added query plan support
+the catalog. A standard feature in all relation databases, the job of a query
+plan is to monitor queries in a live system and based on execution metrics
+devise optimized plans for executing the low level instructions which lead to a
+query result. In sites with large number of indexed objects this can make a
+tremendous difference and significantly speed up all queries.
+The query plan support is completely transparent to all users, though ways
+for developers to predefine it and store it across server restarts. The plan
+itself can be introspected in a tab in the ZMI. There's also a new ZMI tab to
+report slow catalog queries which can help developers to tune the remaining
+queries in their applications.
+In addition to these larger changes there's been a high number of smaller
+changes to the search logic and the catalog implementations. All of these
+should result in better query execution and reduced number of conflict error
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