We made a few major changes to the v1.7 search interface for a big improvement in performance. The first change was to ot use a wildcard for the prefix. Thus when a user searches on NAME, we only search for 'NAME%', in older version we would search for '%NAME%'. This allows mysql to use the index on sort_name and is significantly faster than a full table scan. The second change involved not searching the 'email' table when doing a search on 'name'. This allows us to avoid two very expensive 'LEFT JOIN' sql statement and speeds up search significantly.
You can get around the...Read more