Comments on: Execution plan – more properties

By: Gail

Gail — Thu, 25 Mar 2010 16:08:40 +0000

There’s no single indicator that shows that one query is more efficient than another. Look at the query cost, the output of Statistics IO and the cpu time and duration from Statistics Time

By: Harry

Harry — Thu, 25 Mar 2010 15:25:12 +0000

Hi,
Is there one indicator that I can use to compare the efficiency of two queries

By: Gail

Gail — Mon, 24 Aug 2009 05:54:58 +0000

1) Generally the cost, along with the output of stats IO and Stats time
2) There isn’t one
3) Probably, but you’d have to ask the SQL development team as it’s not public
4) You can’t.

By: TrampXia

TrampXia — Mon, 24 Aug 2009 01:18:51 +0000

Dear Gail:
Could you please help me below issues?
1、When We use different ways to write the script,How to know which SQL statments is more optimization by the executed plan?
2、what’s the mearsuring unit of the I/O Cost、CPU Cost、subtree Cost and Cost?
3、is there any mathematic equation among these costs?
4、How to comput the total accurate time by the execution plan?

By: Raj

Raj — Thu, 26 Feb 2009 15:52:54 +0000

thank you for ur lightening fast response

By: Gail

Gail — Thu, 26 Feb 2009 15:37:36 +0000

The subtree cost is the cost of that operator plus all the operators beneath it in the tree. The subtree cost on the top-most operator will be the cost of the entire query.

By: Raj

Raj — Thu, 26 Feb 2009 15:06:37 +0000

Hi,

Again great post. Another doubt.

I use SQL 2000. So, does the ‘sub tree cost’ property specified in the left corner applies to the entire cost of the query?

Thanks in advance