Error Message 666, The Evil Kills

666    16    Maximum system-generated unique value for a duplicate group exceeded for table ID %d, index ID %d. Dropping and re-creating the index may fix the problem; otherwise use another clustering key.”

So today when running a query I’ve come across the message listed.  Off I went digging the Internet to figure out what exactly this meant.  I guess the fact I was running a query with distinct counts against 2 Terabytes of data has something to do with it. Surprise [:O]

All in all, it is definitely an “evil” error message.

Off to fix the query & index.