Clustered and nonclustered indexes, keys, included columns, and access paths.
113 associated posts109 primary posts
I'm going to tell you a secret. Index tuning is complicated, but it's something you can become great at. You just need to practice it regularly.
Here's that one step: stop thinking index tuning is a problem for Future You.
Recently, Jes asked the team an index tuning question: "If a query has an index hint in it, will the optimizer ever suggest a missing index for that query?"
I immediately loved the question because I'd never really thought about it before. I typically think of index hints as being a very risky game and avoid them whenever I can-- after all if someone drops the index you've hinted, any query hinting a non-existent index will start to fail. (That's a really bad day!)
sp_BlitzIndex® just can't keep a secret. That's a feature, not a bug. I wrote sp_BlitzIndex® specifically so that it would rat out some things that SQL Server is doing behind the scenes to secretly help you out-- because it's really better if you know about it. What are secret columns? SQL Server needs a unique…
When it comes to indexes, SQL Server is really helpful. It lets you see what indexes queries are asking for both in execution plans, and missing index dynamic management views ("DMVs"). I like to look at the DMV missing index requests using sp_BlitzIndex®.
When you look at missing index requests, it's always important to remember one of the biggest things: these missing index requests won't ever ask for or recommend a specific clustered index.
Key length matters in SQL Server indexes.
It's a best practice to keep your index keys as narrow as possible, and SQL Server enforces a maximum key length of 900 bytes on most "normal" clustered and nonclustered indexes.
I have been in love with books and libraries most of my life.
I remember some of my earliest favorites: Little House on the Prairie, Anne of Green Gables, Bridge to Terebithia, The Chronicles of Narnia. I remember feeling grown up when my sixth grade teacher handed me Gone With the Wind.
Scaling up is hard: big hardware gets expensive fast. Scaling out is equally difficult; interesting design problems creep in to scale out solutions. One of the more troublesome issues architects face when scaling out is the issue of distributing identity. It's often advantageous for object identity to be unique and portable across all database instances…
Let’s have a chat about your indexes in SQL Server. Indexes can be confusing. They are the easiest way to boost performance of queries, but there are so many options and terms around indexes that it can be hard to keep track of them. Let’s chat about the differences between clustered and nonclustered indexes, key…
How do you know which indexes to create to improve your database performance? Microsoft Certified Master Kendra Little shows you how to find a missing index, decide on the best index definition, and measure the usefulness of your new index. If you know the basics of what a database index does and want to learn the smart way to design indexes, this talk is for you.
If you're only indexing to make reads faster, you need to think again. Indexes can make every operation in the database faster, even deletes. The Problem: Deletes are Very Slow I was lazily researching new development techniques one day when I received an email from a client asking why deletes could be slow. I rattled…
Paul Randal (Blog - @PaulRandal) nailed a blog post to the church wall entitled, "What 5 things should SQL Server get rid of?" His choices included auto-shrink, putting databases in full recovery by default, GUIDs as clustered indexes, and more. He tagged me, and I knew right away what I'd say. 5. IntelliSense restrictions on…
Sometimes less is more - and indexes are definitely one of those times. Learn how to identify overlapping indexes and why they're so bad for performance, and learn about SQL Server 2005's new INCLUDE feature.
I had to do some developer training last week and I wrote up a paper on the basics of primary keys and indexes. Sure, there's tons of similar stuff around the net, but this is MINE, baby.
Our Table: Phone Numbers
For our evil training purposes, let's say we work for the phone company, and we need a database table with phone numbers. We need to track:
