On Fri, Mar 18, 2011 at 6:10 PM, Barry Hunter <[email protected]> wrote: > > At least some can answer count queries using just index scans - ie > doesnt touch the actual data. Can get close to that with keys_only - > which persumably is just what the index contains - and counting the > rows, but it still requires transfer of all keys to the application (I > think anyway) just to be discarded.
This is what PreparedQuery.countEntities() does. It doesn't transfer keys to the application, but it's still an O(N) operation. Jeff -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
