What is the unit of estimated query coast?

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What is the unit of estimated query coast? how to reduce?

Posted 4-Feb-15 17:38pm

nijilmk

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Snesh Prajapati · Answer 1 · 2015-02-04T17:55:00

Solution 1

As of now it is unitless measure of overall cost. In the SQL Server 7 days, it originally referred to the number of seconds taken to execute on a particular machine. This all is well explained in answer here:
http://dba.stackexchange.com/questions/9982/how-do-i-read-query-cost-and-is-it-always-a-percentage[^]

It is just a ratio as mentioned here "......ratio ~4:96. Notice the lack of units for these costs: they're not in seconds, MB or anything."
http://blogs.msdn.com/b/sqlqueryprocessing/archive/2006/10/11/what-is-this-cost.aspx[^]

Thanks.

Posted 4-Feb-15 17:55pm

Snesh Prajapati

Updated 4-Feb-15 17:59pm

v2

Comments

nijilmk 5-Feb-15 0:39am

seconds,milliseconds,heart beats ?

nijilmk 5-Feb-15 0:40am

what does the estimated subtree cost = 0.6237 mean ? is it 0.6273 seconds,milliseconds,heart beats ?

Snesh Prajapati 5-Feb-15 3:44am

Those are unit-less and meant only for comparison purposes against other alternatives: http://blogs.msdn.com/b/sqlqueryprocessing/archive/2006/10/11/what-is-this-cost.aspx