16Dec 2019 by Grant Fritchey 53 Comments

Why Don’t People Use Columnstore Indexes?

Professional Development, SQL Server
I saw this question on SQL Server Central the other day and had an immediate, visceral reaction. I know why. Now, before I explain my answer, please, let me reassure you. I get it. You're busy. What I'm about to suggest is not meant as a direct critique of you. It's just an observation of the human condition. Heck, maybe I'm wrong. So, before you write the angry screed about how busy you are and why you can't possibly do what I'm about to suggest, believe me, I already understand. I'm still going to suggest something that's going to make some of you angry. Common Knowledge If you'll permit me, I want to talk about Extended Events before we talk about Columnstore. SIDE NOTE: Standing invitation, any time I'm at…
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01Jun 2015 by Grant Fritchey 4 Comments

Parallelism and Columnstore Indexes

T-SQL
Columnstore indexes are fascinating and really cool. Unfortunately, they're adding an interesting new wrinkle to an old problem. What's the Cost Threshold for Parallelism set to on your server? If you just said "The whatsis of whositz?" then the value is 5. The cost threshold is the point at which the estimated cost of an execution plan goes from definitely serial to possibly parallel. This default was set for SQL Server 2000 and hasn't been changed since. I've long argued, loudly, that it's too low. I've suggested changing it to a much higher value. My advice has gone from 35 to 50 and several places in between. You could just look at the median or the mode of costs on your system and use the higher of those values as…
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