Quantcast
Channel: Forum Getting started with SQL Server
Viewing all articles
Browse latest Browse all 7129

Statistics 101 Questions

$
0
0

I appreciate any insight you can offer into any of these  questions:

1.Statistics deal with column data "distribution" in tables. Correct?

2. They are used (along with indexes) by the query optimizer to determine the best execution plan for a query. Correct?

3. Statistics aren't updated automatically. How does one know when a statistic needs to be refreshed (e.g. using sp_updatestats)?

4. If a column has statistics defined on it, the table content is deleted and repopulated, will the statistics be automatically refreshed or will the old statistics remain intact?

5. I don't recall ever creating a statistic (unlike indexes) but the system seems to generate them automatically ("_WA_Sys...."). What triggers it to generate them?

edm2


Viewing all articles
Browse latest Browse all 7129

Trending Articles