I was coincidentally doing a show table status on couple of tables when I saw that one of the MyISAM tables has reach the 4 GB default limit. The table stores all my show processlist parsed data and apparently my parsing and importing script did not notify me of any errors like the table was full or something. Anyway, I solved the problem by running the command below.
ALTER TABLE MAX_ROWS = 1000000000;
A good discussion on MyISAM 4 GB default limit can be found on this link: