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Posted by gherrell on 08/15/06 23:57
That makes sense. However, I didn't express myself very well.
I am looking for validation that this approach with a view gives the
same opportunity for a performance benefit as a parameterized UDF or
straight stored procedure.
Erland Sommarskog wrote:
> gherrell (greg.herrell@gmail.com) writes:
> > I know there is a lot of information already out there on this topic,
> > but given the following scenario...
> >
> > --------------------------------------------------------------------------
> ------------------------------------------------------------
> > Create a view like so ( pardon the pseudo-code )...
> >
> > CREATE View vwContactAddresses
> > Select * FROM Contact INNER JOIN Address ON Contact.ContactID =
> > Address.ContactID
> >
> > And then do a sargable select from the view using a stored procedure
> >
> > CREATE STORED PROCEDURE spSelect_ContactAddresses
> > @ContactID int
> > AS
> > Select * FROM vwContactAddresses WHERE ContactID = @ContactID
> > --------------------------------------------------------------------------
> ------------------------------------------------------------
> >
> > In my understanding, "vwContactAddresses" would be substituted with the
> > actual SQL join statement when the view is accessed.
> >
> > So for the stored procedure in question an execution plan for
> > "Select * FROM Contact INNER JOIN Address ON Contact.ContactID =
> > Address.ContactID WHERE ContactID = @ContactID" would be cached.
> > Correct?
>
> Not really. What is in the cache is a plan for the stored procedure
> spSelect_ContactAdresses.
>
> While the operators in the plan are likely to be same as in the plans
> for "Select * FROM vwContactAddresses WHERE ContactID = @ContactID" and
> "Select * FROM Contact INNER JOIN Address ON Contact.ContactID =
> Address.ContactID WHERE ContactID = @ContactID" they are three different
> cache entries. In fact, the plan is case- and space-sensitive, so all these
> three are different cache entries:
>
> SELECT col1 FROM tbl
> Select col1 FROM tbl
> SELECT col1 FROM tbl
>
>
>
>
> --
> Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
>
> Books Online for SQL Server 2005 at
> http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
> Books Online for SQL Server 2000 at
> http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
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