[Xorlev]

Well, lets see here. What I'd do is grab the userid searched by (either by id, or running the through a query and getting it back).

Note: This uses my knowledge of Sphinx 0.9.8. I'm not sure about the limitations of 0.9.7.

Show all threads by started by user:

PHP Code:

// Other stuff (sorting, etc.)
// Now we grab all threads started by userid.
$cl->SetFilter('postuserid', $userid); 
$cl->Query('', 'thread;threadelta'); 


Here we can then grab the threadids from the matches array.

Show all posts by user:

PHP Code:

// Other stuff (sorting, etc.)
// Now we grab all posts by userid.
$cl->SetFilter('userid', $userid);
$cl->Query('', 'post;postdelta'); 


Grab the postids, retrieve, and show.

Show all threads posted in by user:

PHP Code:

// Other stuff (sorting, etc.)
// Now we grab all posts
$cl->SetFilter('userid', $userid);
$cl->Query('', 'post;postdelta'); 


Now all we have is a bunch of posts. But, what we also have is "threadid" in the attributes of each post. We can collect them, filter duplicates, then retrieve the threads.

Whatever fuzzy matches were done on the username can be done on the user table and returned. The filter value $userid has to be an array anyways, so we can pass it multiple userids we grabbed from the user table. I'm not entirely familiar with vBulletin's classes and such, but I might give it a try to writing in Sphinx 0.9.8 support.

Edit:
I just looked back again and reread this:

# You can only use Sphinx to perform queries that have a full text component. So searches by userid/forumid WITHOUT a key word are not possible. These searches can run on indices though so they shouldn't be an issue.

* Workaround by kmike. "You can emulate the search by user in sphinx by adding a fake unique keyword per each member in the mix (e.g. "_userid_12345"). Searching by this keyword will return all posts by the member with userid 12345."

That's one of the changes in Sphinx 0.9.8. It supports scans, so a blank query returns all results that fall within your filters. Sphinx 0.9.8 will apparently be far easier to implement than 0.9.7.