Performance in SQL key indicators to check

Question

Hi, I am pretty new at MS SQL.

I would like to know a starting point list of parameter to look in EXECUTION PLAN as indicator for good or bad performance in mu query.

For example:

Should I look for Estimated subtree cost for better performance? Any other values to look?

thanks guys for your support

Answer 1

Well you should start looking for a good index coverage.

That means all WHERE, JOIN, GROUP BY, ORDER BY are using an index instead of a table scan. Table Scans are only acceptable in cases where you have a table with a max of like 10 rows. Otherwise it is going to kill performance.

To improove the performance I would suggest that you use the "Database Engine Tuning Advisor" that comes with SQL Server.