最大CPU使用量和>60性能优于MySQL查询

When I first made this query and the table was relatively small, it ran very quickly, but over time as the update table size increased (now about 6000 rows) the query has been extrememly slow and resource intensive. The server I'm using is the 1GB RAM VPS from linode.com, and I haven't actually waited long enough for the query to finish.When I first made this query and the table was