SQL Server

A Common Query Error

So Many Choices When you only need stuff from a table where there’s matching (or not!) data in another table, the humble query writer has many choices. Joins In/Not In Exists/Not Exists No, this isn’t about how NOT IN breaks down in the presence of NULLs, nor is it a performance comparison of the possibilities.…
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Office Hours Podcast

[Video] Office Hours 2018/8/1 (With Transcriptions)

This week, Erik and Richie discuss monitoring tools, finding all unused tables across databases, query tuning, deleting vs hanging on to indexes, sharding databases, query editors, aggressively-locked indexes, why a plan would not be in the plan cache, and Richie’s current housing situation. Here’s the video on YouTube: You can register to attend next week’s Office Hours,…
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A New tempdb Trace Flag Appears!

Coming Around Microsoft has been doing a good job of taking stuff that used to be Wizard Hat and making it part of out of the box functionality. Starting with SQL Server 2016, you didn’t need to keep these in your setup checklist: Trace flag 1118 to reduce SGAM contention Trace flag 1117 so when…
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#TSQL2sday: +

For this month’s T-SQL Tuesday, He of Perfect Hair, Bert Wagner asked, “What code have you written that you would hate to live without?” There are a lot of pieces of code I frequently need to reuse when working on the First Responder Kit, like string splitting, XML PATH-ing, and converting milliseconds to some human…
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Where Clustered Index Keys Dare

Colonel Clustered We’ve blogged a couple times about how clustered index key columns get stored in your nonclustered indexes: here and here. But where they get stored is a matter of weird SQL trivia. You see, it depends on how you define your nonclustered index. “It Depends” We all scream for dependencies! Hooray! If you…
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Parameter Fluid Optimization

Optimizer Studies I don’t have a real job, which means that if something strikes my fancy, like staring at a spot on the wall for an hour, I can do it. Occasionally things are a bit more inspired, and so I go poking around what SMRT PPL might be up to. All you nice people…
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