I've a table with half million records that my application uses continious with several UPDATE e SELECT statement (about 5 requests/sec).
After several (4-5) hours I've a degrade of performance, but if I update the statistics (of thi table) all return ok.
Now the situation is I create a job to maintenance this table updating statististic two times a day ....
Is it normal? SQL should update statistics by itself?
I choose the wrong way or ... what can i do?
Without knowing a lot more about what your configuration looks like, how the table(s) is being used, etc. I'm going to have to guess. If you are changing 15-20% of the rows in the table (from your description), I'd expect to need to update statistics.