the wp_commentmeta table of my wordpress database got huge—too huge for the amount of data its suppose to carry that its bound to be carrying some junk. so i cleaned it up by issuing the following sql statement via phpmyadmin:
DELETE FROM wp_commentmeta WHERE comment_id NOT IN (SELECT comment_id FROM wp_comments)
this brought down the table size from 5.4 megabytes to 32.4 kilobytes! that’s a lot of junk.