Steps to reproduce bad performance :

-Add lots of groups (>200 groups) to a group directory (either SQL or LDAP)

-Add the group directory to the site that is going to be used for testing purposes

-Add a basic search service to a page that returns 1 content

-Measure the zone processing time of the zone containing the search service (debug rendering time logs)

-Label the aforementionned content with the group directory label (root)

-Measure the zone processing time again

Bug

The measured loading time increases significantly (by 200-300ms)