Posted by Erland Sommarskog on 10/25/07 21:22

Ben (pillars4@sbcglobal.net) writes:
> a) Backuped our SQL Server 2000 database
> b) Created an empty database in SQL Server 2005
> c) Restored our SQL Server 2000 database to the empty SQL Server 2005
> database

Not that it's a big deal, but step b was not needed. RESTORE will
create the database if it does not exist.

> Below are the things that I have tried so far, which did not work:
> 1) Rebuilt all the indexes
> 2) Took out the "Refresh" lines that were not needed in the app code
> 3) Set the compatibility level from 80 to 90
> 4) Dropped the "dtproperties" system table, which are not being used
> anymore in SQL Server 2005
>
> Any ideas would be great! Thanks!

You will need to analyse the query plans for these slow queries to see
what is slow in them. If possible compare the query plans to what you had
in SQL 2000. Maybe you need to improve your indexing, maybe the queries
needs tweaking.

You can examine the query plan by running the query from Mgmt Studio
with Show Execution Plan enabled. You can also use Profiler and catpure
the Performance:Showplan XML event. This is particularly useful, if
it's difficult to extract the query from the application.

So why do these queries perform worse with SQL 2005? Well, an optimizer
is a guessing game. From statistics sampled about the data, the optimizer
makes an estimation what is the best query plan. Each new version of
SQL Server comes with new neat tricks in the optimizer, but there always
queries where these improvements backfire.
--
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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