Posts by Brent Ozar

Why Order Isn’t Guaranteed Without an ORDER BY

Start with the Stack Overflow database, with no nonclustered indexes. If you’ve been playing around with demos, run my DropIndexes proc just to clear things out, which leaves the clustered indexes in place. Say you run this query: Transact-SQL SELECT TOP 100 Id, DisplayName FROM dbo.Users; 12 SELECT TOP 100 Id, DisplayName  FROM dbo.Users; By default,…
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The Silent Bug I Find in Most Triggers

Get Notebook – FAQ I don’t have a problem with triggers. They get the job done when you need to implement business logic in a hurry, and you’re not allowed to change the application. As long as you keep the number of statements to a minimum (say, 2-3), and don’t try to do something really…
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Pop Quiz: SQL 2000 Bug or SQL 2017 Bug?

2002: Me and Bailey, mom’s Great Dane When I was thinking about this site’s 17th birthday, I started wondering: back in 2002, what bug might I have been working with in SQL Server? I started reading back to the list of bugs fixed in SQL Server 2000 Service Pack 1, and it hit me…these bugs…
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Brent Ozar's Consultant Toolkit

Updated First Responder Kit and Consultant Toolkit for April 2019

This month, lots of improvements and bug fixes, including checking for paused resumable index operations, Evaluation Edition expiration dates, sp_BlitzCache shows the number of duplicated plans for each query, sp_BlitzIndex will skip a list of databases for you, and more. To get the new version: Download the updated Azure Data Studio users with the…
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Free SQL Server Load Testing Tools

So you wanna run a load test against SQL Server. One thing I need you to understand first: you have to provide the database and the queries. Almost all of the tools in this post, except the last one, are designed to help you run queries, but they don’t include the queries. The whole idea…
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