Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

On a SQL server, why do we need a weekly update stats job (with full scan) when we have AUTO_UPDATE_STATISTICS=ON for all databases?

Doesn't this option update statistics all the time?


share|improve this question
up vote 1 down vote accepted

Yes and no, it depends on the table size and the number of rows being updated whether status updates will be triggered; an occasional rebuild is a good idea. Some info on the algorithm for auto updates

share|improve this answer
it depends on the table size and the number of rows being updated ? can you please give me an example? – Manjot May 13 '10 at 0:35
See link posted above. Stats get updated when a threshold is crossed, not after every update; it's not uncommon to not use auto_update so updates don't happen at random intervals (they're not random, but tell that to the user that just updated a record that triggered the update, causing a blip in performance while stats get updated). If you turn off auto_update, you MUST do occasional rebuilds. – SqlACID May 13 '10 at 0:45
Thansk a lot for this article – Manjot May 13 '10 at 2:00

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.