Which tables are supposed to have two primary keys?

fmimoso

After reading Mark's Lussumo downtime post, I checked my database and, besides what he diagnosed, I have five other tables that have two primary keys:

LUM_UserDiscussionWatch as pictured:



And (LUM_Comment,) LUM_CategoryBlock, LUM_DiscussionUserWhisperFrom, LUM_DiscussionUserWhisperTo, LUM_ThankfulPeople and LUM_UserBookmark.

My question: is this supposed to be like it is now? Or, is there a misconfiguration with these settings?
I'm asking this because my shared server's CPU load is always at +10... and I was wondering if I'm not the culprit...

TIA

Dinoboff

It is one primary key made from 2 fields. In the case of the comment, it is unnecessary. It is normal for the other ones.

Dinoboff

In the case of the comment table it was not necessary to add the discussion_id to the primary index because the comment_id is already unique. But what made the queries on the comment table slow was the absence of an index on the discussion_id field.

fmimoso

Following your comment, here's my LUM_Comment table:



Can I ask you kindly if you suggest any changes?
As you can see it's getting big... and I wouldn't want it to begin crashing...