Tips, Tricks, and Advice from the SQL Server Query Optimization Team

Renaming/Moving Blog

After a few months, we're pretty happy with the content and readership we have created. This is a...

Author: QueryOptTeam Date: 09/20/2006

SQL Customer Advisory Team

I've been busy reading the SQL Customer Team's blog. Lots of good data on how to build a good...

Author: QueryOptTeam Date: 09/14/2006

How to Read Statistics Profile

(2006-09-01 added a paragraph on parallel query plans) In SQL Server, “Statistics Profile” is a mode...

Author: QueryOptTeam Date: 08/29/2006

Locking Backgrounder

A quick post for today. It's actually more of a storage engine concept, but you'd be surprised how...

Author: QueryOptTeam Date: 08/01/2006

UPDATE STATISTICS undocumented options

If you read the Books Online page describing the UPDATE STATISTICS command, you will see that there...

Author: QueryOptTeam Date: 07/21/2006

Hints for DML queries

Not everyone knows that query level hints (like loop join) will impact the entirety of a DML query...

Author: QueryOptTeam Date: 07/14/2006

Non updating updates

A question we are frequently asked is what happens when an update statement assigns a column to its...

Author: QueryOptTeam Date: 07/07/2006

Fun for the day - Automated Auto-Indexing!

We've been hard at work up here on a little prototype for you guys to try. This attachment is a...

Author: QueryOptTeam Date: 06/01/2006

Row Goals revisited - FAST hint guidance

A question came in about when to use the FAST hint. If you remember from the row goals post...

Author: QueryOptTeam Date: 05/03/2006

Ordering Guarantees in SQL Server 2005

SQL is a declarative language that returns multi-sets (sets allowing duplicates) of rows. The...

Author: QueryOptTeam Date: 05/02/2006

Local-Global Aggregation

Today's topic is a general primer on something that is called "local-global aggregation"....

Author: QueryOptTeam Date: 04/18/2006

T-SQL Procedural Blog

I ran into one of my colleagues in the hallway the other day from another part of the product, and...

Author: QueryOptTeam Date: 04/12/2006

Sorted Seeks

The Optimizer model makes several assumptions when making plan choice decisions. These decisions can...

Author: QueryOptTeam Date: 04/12/2006

Indexed Views in SQL Server 2005

I'd like to point you to a white paper that Eric, one of our program managers, did on Indexed Views...

Author: QueryOptTeam Date: 04/11/2006

Optimizing Distributed Queries

I saw a post in one of the newsgroups today that referenced a piece of information Microsoft...

Author: QueryOptTeam Date: 04/06/2006

Why should I create an index?

There are many cases where the database administrator does not control the queries being submitted...

Author: QueryOptTeam Date: 04/06/2006

I Smell a Parameter!

Parameters are a useful way to improve overall system performance when there are many common queries...

Author: QueryOptTeam Date: 03/31/2006

Row Goals in Action

Today, we'll talk about row goals. The optimizer in SQL Server has a feature that can bias plan...

Author: QueryOptTeam Date: 03/30/2006

Migrating Cardinality Eestimation Posts from Previous Blog

Ian had a blog that contains a number of interestig tips/tricks, mostly about cardinality estimation...

Author: QueryOptTeam Date: 03/27/2006

TOP 100 Percent ORDER BY Considered Harmful.

(Updated 2006-27-03 9:00am Pacfiic Time - at the bottom) SQL is a declarative language. That means...

Author: QueryOptTeam Date: 03/24/2006

Using Computed Columns to Fix Scalar Expression Estimation Errors

(Ok, let's try something a bit more involved now. Here's a tip on how you can use computed columns...

Author: QueryOptTeam Date: 03/24/2006

Query Recompilation Details

SQL Server contains self-tuning functionality that will recompile your query as the source data...

Author: QueryOptTeam Date: 03/24/2006

Statistics in SQL Server 2005 White Paper

Statistics is one of the most challenging areas of our product. While we have automated a number of...

Author: QueryOptTeam Date: 03/24/2006

Greetings!

On behalf of the Query Optimization Team for Microsoft's SQL Server product, welcome to our humble...

Author: QueryOptTeam Date: 03/24/2006