How can you tell if an index is REALLY a duplicate?

There’s a lot of confusion around duplicate indexes and I think a lot of it has to do with how sp_helpindex (or even SSMS) display what’s in an index. What’s actually in the index – and how it’s structured – are not always what they seem. This was the original motivation behind my rewrite of […]

More considerations for the clustering key – the clustered index debate continues!

OK, I've talked about the clustering key many times. Here, I thought I'd bring together one final series of details (and links) to help you really understand why I'm so adamant about DESIGNING a clustering key and not just letting SQL Server pick it for you (for example when it defaults to making the primary […]

(OLD): A new and improved sp_helpindex (jokingly sp_helpindex8)

NOTE: I’ve released other versions of sp_helpindex since this post. Check out the category: sp_helpindex rewrites for all of the options! OK, I first blogged about re-writing sp_helpindex here as sp_helpindex2 (April 2008). Shortly thereafter (Aug 2008), a reader found a bug and when I went digging, so did I (a couple of others). I did […]

Filtered indexes and filtered stats might become seriously out-of-date

Time flies when you're having fun, eh? This week Paul and I are in Dublin, Ireland delivering a deep technical "SQL Immersion Event" on Internals, Performance Tuning and Maintenance with our partner ProData (and having a blast – we have a really fun and very interactive group). And, today's an even more interesting day to be in […]

Column order doesn’t matter… generally, but – IT DEPENDS!

OK, for years I've been saying that SQL Server doesn't care about the order in which you define the columns of your table because internally SQL Server will re-arrange your columns to store all of the fixed width columns first and the variable columns last. In both the fixed-width portion of the row as well […]

Companion content for Chapter 6 (Index Internals) of SQL Server 2008 Internals

Recently, the SQL Server 2008 Internals title was released (and only in the past few days have people actually received their copies)! In fact, I still haven't seen the book in person… soon though! Anyway, Kalen, Paul, Conor, Adam and I worked to create a comprehensive resource on SQL Server 2008 internals and to supplement the written […]