Huge Operator cost in Estimated execution plan - by Sankar Reddy

Status : 

  Won't Fix<br /><br />
		Due to several factors the product team decided to focus its efforts on other items.<br /><br />
		A more detailed explanation for the resolution of this particular item may have been provided in the comments section.


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ID 436184 Comments
Status Closed Workarounds
Type Bug Repros 4
Opened 4/29/2009 2:08:16 PM
Access Restriction Public
Primary Feedback Item 370798

Description

While testing the performance of large queries (due to lack of production size copies), Estimated execution plan is used. But the operator costs are being showed incorrectly from the estimated execution plan for certain TSQL constructs even if the stats are upto date. It helps if this issue is corrected.

Here is some notes on this issue.
http://sankarreddy.com/2011/03/little-fun-with-estimated-execution-plan/

Upon feedabck from Erland, moving to tools from SQL Engine.
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Posted by Nikhil [MSFT] on 3/30/2010 at 10:40 PM
Hello Sankar,

Thank you for reporting the problem via connect. I apologize for the delay in responding to this.
There is a similar bug that we are tracking for this issue - http://connect.microsoft.com/SQLServer/feedback/ViewFeedback.aspx?FeedbackID=370798 which we are considering for the future release. Given this, I am going to resolve your issue as duplicate of the other issue. In case you have any question or comments then contact me directly at nikhilku@microsoft.com

Thanks,
Nikhil Kumar
nikhilku@microsoft.com
Posted by Boris [MSFT] on 5/18/2009 at 2:55 PM
Hello Sankar,

Thank you for the feedback! If I understand you correctly, the issue you are reporting is related to how Management Studio reports percentages of the operator cost in the batch. In this particular case, the percent cost of the statements in the THEN-part is computed relative to the cost of the query in the IF-part of the statement which may be completely unrelated.

Until this is fixed, the workaround obviously is to ignore the percentage but look at the estimated value itself. The estimated values can be observed for each operator by holding mouse pointer over a particular node (or by looking at the node properties – default shortcut is F4).

Regards,
Boris Baryshnikov.
SQL Server Engine
Posted by Adam Machanic on 4/30/2009 at 7:18 AM
Oh, come on, what's a few million percent among friends??!