Tuesday, August 08, 2006
Estimated CPU Cost and Estimated I/O Cost in Actual Query Plan?
Someone help me - I'm obviously missing something here... In SQL Server 2000 if you use the Query Analyzer with Ctrl+K to include the "actual" execution plan, the execution plan nodes do not say the word "Estimated" in from of CPU Cost and I/O Cost.
When you move to SQL Server 2005's SQL Server Management Studio and choose the "Include Actual Execution Plan" option, it adds the word "Estimated" in front of each ("Estimated CPU Cost" and "Estimated I/O Cost" among others).
Has there been a change in architecture? In both versions, SET STATISTICS PROFILE ON always uses the word "Estimated" in its output which leads me to think that it isn't an architecture change, but rather it's just a decision to add the term "Estimated" to the SSMS output.
The reason I post this is because I had a student ask about the difference in wording in the graphical plans and, to the best of my googling/BOL'ing, I could find nothing that said there's been any change in the use of "estimated".
Anyone have any more details? Maybe I'm just rambling... The documentation only mentioned the "estimated" versions - here
When you move to SQL Server 2005's SQL Server Management Studio and choose the "Include Actual Execution Plan" option, it adds the word "Estimated" in front of each ("Estimated CPU Cost" and "Estimated I/O Cost" among others).
Has there been a change in architecture? In both versions, SET STATISTICS PROFILE ON always uses the word "Estimated" in its output which leads me to think that it isn't an architecture change, but rather it's just a decision to add the term "Estimated" to the SSMS output.
The reason I post this is because I had a student ask about the difference in wording in the graphical plans and, to the best of my googling/BOL'ing, I could find nothing that said there's been any change in the use of "estimated".
Anyone have any more details? Maybe I'm just rambling... The documentation only mentioned the "estimated" versions - here
