commentmeta table size increased too much

with the time the size of wp_commentmeta has increased to a number of MBs, i think every comment has some records based on the comment_id.
say there is a commentator from facebook “ABC” who have some repeated records for social_account_id,social_profile_image_url, etc in this table for every comment. while his profile id and profile picture url are redundant
If we can do that one commentator’s records are created only once?

http://ww.wp.xz.cn/extend/plugins/social/