T.Ashish (9/18/2013)
Thanks for your explanation.So, should I conclude that I do not have to rely on Execution Plan for optimization of my query. Instead, I should check it only for any execution warnings, index usage, look ups, table scan, etc.
And does same applies to I/O stats !!
The execution plan tells you what is happening within the optimizer. It is not a measure of performance, but is, instead, an explanation of performance. And, as my blog post said, while you can't trust those numbers, they are the only ones you get, so you will use them to understand what is happening within a plan. Just don't assume that they accurately reflect reality in all cases.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning