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A deep dive into hash tables, part 1| SQLServerFast
We all know the Hash Match operator. It joins or aggregates data, based on a hash table. That hash table is ideally stored in memory. But if the granted memory is insufficient, then Hash Match will spill to tempdb, which is slow. I assume that every reader of this blog knows this already. But what...| SQLServerFast
The 183rd edition of T-SQL Tuesday is hosted by Steve Jones. He has picked everyone’s favorite (cough) topic: permissions, and how to manage them. I am lucky. With my specialization in query performance tuning, I don’t often have to deal with permissions. (Well, apart from of course not getting the permissions I need to do...| SQLServerFast
(I wrote this well in time. Really. I swear. And then … forgot to publish it in time. Oh well. This will then be my T-SQL Wednesday, I guess?) Welcome to the first T-SQL Tuesday of 2025. Hosting duty this time falls on Rob Farley’s shoulders. And he has found a great topic: Integrity. I...| SQLServerFast
It’s December. The last month of the year, and hence also the last T-SQL Tuesday of the year. Edition 181 is hosted by Kevin Chant. His chosen topic for this episode is to have us talk about which SQL Server announcement excited us the most. This posed a bit of a problem for me. The...| SQLServerFast
Another month, another T-SQL Tuesday. Edition 180 already. Our host is Josephine Bush, and she opens a topic that hits close to home for me: is good enough, perfect? I know my weaknesses. I know that my perfectionism is one of them. I know that striving for perfect is not always the best thing to... The post T-SQL Tuesday 180 – The enemy of good? appeared first on SQLServerFast.| SQLServerFast
November is near. Traditionally (in the USA, at least) the month of the Black Friday sales. I have decided to once more join in on that tradition! During the entire month November 2024, I offer a 50% discount on all prices for the SQLServerFast Execution Plan Video Training. And that discount even stacks with the... The post Black Friday again appeared first on SQLServerFast.| SQLServerFast
This post is for T-SQL Tuesday 178, hosted by Deepthi Goguri. She invites us to write about a recent technical issue we resolved. So let’s talk about the time I discovered that information in the Query Store might not be what it appears to be. Unexpected delays I was hired by a customer who had... The post T-SQL Tuesday 178 – Misleading data in Query Store appeared first on SQLServerFast.| SQLServerFast
Welcome back to my plansplaining blog series, where I dissect execution plans in order to increase our understanding of how SQL Server processes specific queries. We’re at part 33 already, and I’m still looking at cursors. After discussing the basics, static cursors, dynamic cursors, and keyset cursors, I will now look at the last of... The post Plansplaining part 33 – Fast forward cursors appeared first on SQLServerFast.| SQLServerFast
Welcome to plansplaining, part 32, where we once more look at cursors. We already discussed the basics, and looked at static cursors and dynamic cursors. It is now time to cast our gaze upon the keyset cursor. The keyset cursor is sort of in between the static cursor (which presents a snapshot of the data... The post Plansplaining part 32 – Keyset cursors appeared first on SQLServerFast.| SQLServerFast
I sometimes hear that query performance tuning is a dying skill. But that is not true! Even in the modern day, with workloads moving to the cloud where you can increase performance by just moving a slider, where a lot of work is done by data analysts, using low-code or no-code solutions with an abstracted... The post Execution plan training around the world appeared first on SQLServerFast.| SQLServerFast
