does this cause too much load on the server?
Also, if topics are already locked, will it recheck them?
It seems to be resource-intensive on large forums. While fiddling with it, I noticed the script was triggered when I (or any member?) first visit the forum after auto_lock_next has come and gone, so I was able to reset auto_lock_next in the database as needed and get a rough idea of resource usage.
In the biggest section of the forum with 4700 unlocked topics (with about 3/4 to be locked based on my settings), mysqld usage would shoot up to 70% CPU for about three minutes (on a 2.4GHz P4 w/ 1GB RAM) before coming back down, and no
topics would get locked. However, on my next-biggest forum with 3400 topics, it managed to lock them successfully after a couple of minutes. After I manually locked a couple of thousand topics in the 4700-topic forum, the script managed to successfully lock the rest after 2-3 minutes processing.
I thought this resource hungriness may have been due to the number of posts that needed locking initially, but it turns out it takes almost as much time just for the checking. For the forum with 4700 topics, it takes just over two minutes to process when none need locking.
I like the mod and, as it is, it may be as efficient as it can be. But I thought this aspect of the script should be made known for the benefit of those with larger forums.