[N!ck]

this hack will save you a huge amount of space. rather than storing the beginning of the first post of a thread, it stores only the ID of the first post!

if you DO want to change back over, you'll need to drop the extra field in your "thread" table and do some modifications to newthread.php and forumdisplay.php (and perhaps some un-modifications to other files as well ), then run the install script. really all the install script does is creates the new field ("firstpostid") and goes through each thread (this may take some time and bandwidth depending on the number of threads you have - my fairly new board had about 20 threads and the install script still went as fast as lightning), getting the ID of the first post and storing it.