Development

[Video] How to Find Queries Using OPTION RECOMPILE (And Their Parameters)

Development, Videos
1 Comment
For years, I hated troubleshooting servers with high CPU usage caused by queries constantly asking for new execution plans. Hated it. SQL Server just doesn’t make it easy to find queries with recompile hints. Then Erik Darling’s sp_HumanEvents came along. And now troubleshooting frequent compilations is as easy as this: Transact-SQL EXEC dbo.sp_HumanEvents @event_type =…
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Your Views Aren’t The Problem. Your Code Is.

T-SQL
37 Comments
“I hate views,” the DBA said. “They kill performance. And nested views are even worse.” Wrong. I’ll prove it. I’m going to use the 50GB StackOverflow2013 database, and I’ll start by creating a couple of indexes on the Users table to help our queries, then create a view on the Users table: Transact-SQL USE StackOverflow2013;…
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Free Webcast on Dynamic SQL Pro Tips

Dynamic SQL is one of the most powerful tools in the database developer’s arsenal. When you need a complex search stored procedure that takes all kinds of parameters (price, category, location, color), dynamic SQL can run extremely quickly by leveraging better indexes. However, when done wrong, it’s extremely painful to troubleshoot. I’ve been working with…
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How to Track Performance of Queries That Use RECOMPILE Hints

Say we have a stored procedure that has two queries in it – the second query uses a recompile hint, and you might recognize it from my parameter sniffing session: Transact-SQL CREATE OR ALTER PROC dbo.usp_SearchUsers @Reputation INT AS BEGIN /* Query 1, always the same: */ SELECT COUNT(*) FROM dbo.Users; /* Query 2, recompiles…
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WHERE GETDATE() BETWEEN StartDate AND EndDate Is Hard to Tune.

Development, Indexing
19 Comments
Say you’ve got a memberships (or policies) table, and each membership has start & end dates: Transact-SQL USE StackOverflow; GO DROP TABLE IF EXISTS dbo.UsersMemberships; CREATE TABLE dbo.UsersMemberships (Id INT IDENTITY(1,1) PRIMARY KEY CLUSTERED, UserId INT NOT NULL, StartDate DATETIME NOT NULL, EndDate DATETIME NOT NULL, CancelledEarlyDate DATETIME NULL); GO 1234567891011 USE StackOverflow;GODROP TABLE IF…
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How to Pass a List of Values Into a Stored Procedure

T-SQL
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Say we have a stored procedure that queries the Stack Overflow Users table to find people in a given location. Here’s what the table looks like: And here’s what my starting stored procedure looks like: Transact-SQL CREATE OR ALTER PROC dbo.usp_SearchUsersByLocation @SearchLocation NVARCHAR(40) AS SELECT * FROM dbo.Users WHERE Location = @SearchLocation ORDER BY DisplayName;…
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[Video] Watch Brent Tune Queries

Execution Plans, Videos
13 Comments
Ever wonder somebody else does it? Watch over my shoulder as I spend 9 minutes in PowerPoint explaining the big picture, and then about 40 minutes working on this stored procedure in the StackOverflow2013 database: If you enjoy that, the Watch Brent Tune Queries page has another video and other query examples. Enjoy!
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How to Remove Times from Dates in SQL Server

T-SQL
34 Comments
Say that you’ve got a table with a datetime column in it, like the LastAccessDate column in the Stack Overflow Users table: And let’s say you wanna find the users who last accessed the site on September 9, 2018 – regardless of the time. Here are a few ways to do it: Transact-SQL SELECT *…
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Cool Query Hints

T-SQL
12 Comments
The SQL Server documentation has a pretty cool list of query hints: Yeah, I surf in dark mode. I’m a dark kinda guy. But wait – what’s that colored box? ENHANCE! I could make jokes here, but … every single thing in that caution is true. SQL Server really does typically select the best execution…
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