In 188.8.131.525 we have a productive DB which has run for months now. Today we noticed heavy performance degradation. After inspecting some plans we realized, that NO index was considered by the optimizer at all. After investigating some time indexes are used again. Still sporadically even for the same statement no index is used and not even considered in the plan (1 out of 10 tries).
Has anyone had this before, that the database server was out of a sudden refusing to consider an index on any table in the db?
I have to correct me, the problem disappeared after restart of db server. So I assume it was a one time incident. If it will reoccur I will provide more information, thanks for all answers and comments.
answered 28 Jan '12, 06:52