[CarCdr]

I have made some optimizations to attachment_browser to improve the speed of the queries.

1. Only include a table JOIN if it is really required.
   We look at a query before running it to determine which tables to join. Before, we would always include all tables in addition to attachment: user, post, thread, forum.
2. Do not use a forum table JOIN.
   Got rid of references to 'forum.forumid' and 'forum.title'. Retrieve the forumid from the thread table join, which we likely need anyway for checking thread.forumid. Retrieve the forum titles for the page after the fact using the forum cache. The only time we need the forum table JOIN is when user request a sort by forum title.
3. Include forum access check only if required.
   The check for "thread.forumid IN (Accessible-Forumids)" is included only if required -- only if user does not have access to all forums.
4. Be default, there is no sub-sort (i.e., 2nd-level sort)

As a result, the two queries do run faster for default display.

Query #1: The 'COUNT(*)' query runs anywhere from 20% faster to 5 times faster (MySQL caching must explain this huge range.) This was by far the slower of the two queries.

Query #2: The row retrieval query to get the rows for the target page runs about 9% faster, but that is not so important as it was the fast query anyway.

PM me an e-mail and I'll send you the new version. Once we agree that things still work properly and you verify the performance increase, I will post the new version here.

Cheers