actually the problem seems to be in the code:
if you don’t have any moderation keywords set every comment gets approved in check_comment function:
…
$mod_keys = trim( get_settings(‘moderation_keys’) );
if (” == $mod_keys )
return true; // If moderation keys are empty
so add a moderation key…
I had the same problem, but i see my wp_options tables has no entry for “comment_whitelist” so somehow the install didn’t create it.
I would suggest a 1.6 resolution of an on-use cache with a fixed limit.
So once you lookup the user, cache the info for a certain time. Limit the list to a reasonable number and do a least recently used replace.