Posts by Brent Ozar

Brent Ozar

2460 posts

https://www.brentozar.com

I make Microsoft SQL Server go faster. I love teaching, travel, cars, and laughing. I'm based out of Las Vegas. He/him.

Building SQL ConstantCare®: I Love Unit Tests

Last Updated May 14, 2018

Brent Ozar

Development, SQL ConstantCare

You know what my biggest regret is about sp_Blitz? No unit tests. Seriously. Back then, I wrote a bunch of T-SQL checks to see if a server had memory configuration errors, corruption, obscure trace flags, etc. Over time, sp_Blitz got bigger and bigger, and we started getting code contributions from strangers. Things got even more challenging…

Today’s Press Conference Transcript: I’m Running for Database Administrator General

Last Updated May 13, 2018

Brent Ozar

Humor

Thanks for joining me today – I know you reporters are all really busy, and I appreciate you taking the time to attend this press conference. I’d like to start off by formally announcing my candidacy for Database Administrator General. There’s a lot of great candidates out there, but I think it’s time for me…

Book Review: Microsoft SQL Server Training, Volume 1

Last Updated December 9, 2018

Brent Ozar

Book Reviews

Last week, I shared a few pictures out of Ron Soukup’s Inside SQL Server 6.5 book. You had a blast with that one, so I figured I’d share some more pictures from another, uh, let’s call it “well-preserved” book about SQL Server. Make sure you see the subtitle of this book before you add it to your…

The DeWitt Clause: Why You Rarely See Database Benchmarks

Last Updated May 7, 2018

Brent Ozar

SQL Server

Back in the early 1980s, Dr. David DeWitt – who you might know from past PASS Summit keynotes, formerly of Microsoft (LinkedIn) – was working on measuring database performance. His team wrote a benchmark, ran it against Oracle, and Oracle didn’t fare well in the results. Oracle reacted as one would expect – they were…

Availability Groups Bug with Indexed Views

Last Updated May 7, 2018

Brent Ozar

Breaking News, SQL ConstantCare

The short story: if you drop an index on an indexed view, queries on the Always On Availability Groups replicas that point to that indexed view will cause memory dumps. The long story: to reproduce – AND DO NOT DO THIS IN PRODUCTION – on the primary, create a couple of tables, an indexed view,…

Book Review: Inside SQL Server 6.5

Last Updated December 9, 2018

Brent Ozar

Book Reviews

Books Offline 30 years ago, back in 1988, Microsoft, Ashton-Tate, and Sybase got together to start building SQL Server 1.0 for OS/2. I wanted to take a trip down memory lane to celebrate, but I didn’t wanna go back quite that far. I wanted to go back to what would probably be fairly recognizable – say,…

Building SQL ConstantCare®: Refining Our Recommendations

Last Updated April 29, 2018

Brent Ozar

SQL ConstantCare

One of the fun things about building SQL ConstantCare® as a cloud-based service is that we can iterate fast, making improvements based on the data we find. We can assess the population as a whole, figure out what people are doing well, and look more closely at the rules they’re struggling with. What checks are…

How to Delete Just Some Rows from a Really Big Table: Fast Ordered Deletes

Last Updated June 20, 2021

Brent Ozar

Locking, Blocking, and Isolation Levels

Say you’ve got a table with millions or billions of rows, and you need to delete some rows. Deleting ALL of them is fast and easy – just do TRUNCATE TABLE – but things get much harder when you need to delete a small percentage of them, say 5%. It’s especially painful if you need…

Concurrency Week: Can SELECTs Win Deadlocks?

Last Updated September 10, 2023

Brent Ozar

Deadlocks

Yes, especially when they’re part of a larger transaction. In this example, I’m going to use a database in Read Committed Snapshot Isolation (RCSI), my favorite isolation level for building new applications from the ground up. Optimistic concurrency (aka MVCC) helps avoid a lot of blocking issues – but not all of them. In a…

Building SQL ConstantCare®: Why We Avoided Graphs

Last Updated April 23, 2018

Brent Ozar

SQL ConstantCare, Wait Stats

When we started building SQL ConstantCare®, one of my early decisions was to focus on a text-based interface. I wanted to just simply tell you what I’d do in your shoes. If users wanted to see more evidence behind the recommendations, I’d show it – but otherwise, I’d hold off and let them ask. The experience has…

Does an Index on Just The Clustering Key Ever Make Sense?

Last Updated April 20, 2018

Brent Ozar

Indexing

Say you’ve got a table – in this case, I’m using the Stack Overflow Posts table, which holds all of the questions and answers: StackOverflow.dbo.Posts See the clustered index at the bottom? It’s on the Id field, which is an identity – starts at one and goes up to a bajillion. So it would be…

Building SQL ConstantCare®: The Database

Last Updated December 7, 2019

Brent Ozar

SQL ConstantCare

I bet, dear reader, that this is the post you’ve been really curious about in my behind-the-scenes posts. Back in the post about the data we collect, you may remember that our initial goal was to analyze high-priority issues like missing backups or corruption check, priority boost on, offline NUMA nodes, etc. To do that,…

Training Week: Data Science Fundamentals with a Real Project

Last Updated April 4, 2018

Brent Ozar

Company News

When Steph Locke first ran her Data Science Fundamentals with R class, I was amazed at the work she put into the hands-on labs for the students. They had real challenges to help them learn how to model different kinds of data and learn answers from it. I immediately said to her, “Hey, I wanna give…

Training Week: Announcing Ben Miller’s PowerShell for DBAs: Level 2

Last Updated April 11, 2018

Brent Ozar

Company News

Drew Furgiuele‘s PowerShell for DBAs class has been getting rave reviews, including: “Fantastic class! This is the best online training I’ve ever taken. Very slick setup using the webinar for learning, an AWS VM for labs, and slack for interacting with the class. This course teaches more than just PowerShell for SQL Server – the…

Training Week: Announcing Edwin’s New Class on Failover Clustered Instances

Last Updated April 11, 2018

Brent Ozar

Clustering, Company News

This week, we’ve got a bunch of announcements about new training classes. Next up, Edwin Sarmiento: his 3-day Always On Availability Group class has been getting great reviews: “This class is fantastic. There is no filler, and no needless repetition, so be prepared to pay attention the entire duration. Edwin clearly is very passionate about…

Performance Tuning in 21 Demos at the PASS Summit 2018

Last Updated October 21, 2018

Brent Ozar

#SQLPass, Company News

Performance Tuning in 21 Demos You’re a developer or DBA who wants to tune indexes and queries to make your application go faster. You don’t like learning by watching slides or reading white papers – you want to jump right into the code and see what happens. You’re the kind of person who loves watching…

Kalen Delaney SQL Server Internals Training

Training Week: Announcing a New Instructor: Kalen Delaney!

Last Updated April 10, 2018

Brent Ozar

Company News

Kalen Delaney has been a Microsoft MVP for SQL Server since 1993. She is the author of several highly regarded books, including Microsoft SQL Server 2012 Internals, SQL Server Concurrency, SQL Server MVP Deep Dives, and SQL Server Internals of In-Memory OLTP. Somewhere around a decade ago, she sold a training video CD that was the first SQL Server…

Building SQL ConstantCare®: 10% of you have Priority Boost on.

Last Updated April 10, 2018

Brent Ozar

SQL ConstantCare

One of my favorite things about my job is being able to take the pulse of how real companies are managing their databases. I don’t wanna be locked in an ivory tower, preaching down to you, dear reader, about how you should be doing five million things a day – when in reality, you’re struggling…

Building SQL ConstantCare®: The Minimum Viable Product (MVP)

Last Updated April 10, 2018

Brent Ozar

SQL ConstantCare

When you wanna build something, how early do you let the public in? Where do you draw the lines with the features you absolutely have to have – versus the stuff you just want? Code is never really done. The lines are so blurry these days with labels like Alpha, Beta, Private Preview, Public Preview,…

Building SQL ConstantCare®: What Data We Collect (and What We Avoid)

Last Updated April 10, 2018

Brent Ozar

SQL ConstantCare

Next up in my series of behind-the-scenes posts about our new SQL ConstantCare®, let’s talk about the kinds of SQL Server diagnostic data we’re gathering, why, and what data we’re steering clear of for now. (Psst – read through to the end for a huge, crazy discount today, too.) We – you and I – are…