Execution Plans

The Pleasure Of Presenting With Joe Obbish

Last Updated November 26, 2020

Execution Plans, GroupBy Conference, Indexing, Videos

Grouple On At the December 2018 GroupBy I had the honor of co-presenting with one of the smartest guys around, Joe Obbish. Here’s the video of our session, “The Problems With Optional Operators”, and a link to the resources. Enjoy! Resources: Slides and Demos

Why Do Some Indexes Create Faster Than Others?

Last Updated January 2, 2019

Erik Darling

Execution Plans, Indexing

To warn you ahead of time, this post is an exploration without an answer (yet). There’s some interesting stuff in here, but no conclusions. If that’s not your kind of post, feel free to skip it. If it is, well, here goes nothin’… Wild, Wild Life Creating indexes is kind of a funny thing. By…

When Does SARGability Matter Most?

Last Updated August 9, 2019

Erik Darling

Execution Plans, Indexing

!erehT iH I know what you’re thinking. Another post about how you should just never do this one thing and all your queries will magically end up faster. Just watch the video. For more reading, check out these posts: Sargability: Why %string% Is Slow Optional Parameters and Missing Index Requests Computed Columns: Reversing Data…

5 Ways to Change Execution Plans Without Tuning

Last Updated December 26, 2018

Brent Ozar

Execution Plans

A couple years back, I realized there were at least Ten Ways to Set MAXDOP. These days, as I write and tune queries, I realize there are an awful lot of ways to change the Cardinality Estimator (CE) and Query Optimizer, too. Let’s take a quick survey of five intriguing options. 1. Change your SQL…

Query Store And Cruel Defaults

Last Updated December 19, 2018

Erik Darling

Execution Plans, Query Store (QDS)

Gosh Darn Now, look, it’s no secret that I think Query Store is cool. Heck, I went and wrote sp_BlitzQueryStore so you can examine it similarly to how sp_BlitzCache looks at the plan cache. For a variety of reasons, though, we run into people who can’t or won’t turn it on, or who had to turn…

Never Judge A Query By Its Cost

Last Updated December 12, 2018

Erik Darling

Execution Plans

Signs and Numbers When tuning queries, or even finding queries to tune, there’s a rather misguided desire to look for queries with a high cost, or judge improvement by lowering query cost. The problem is that no matter what you’re looking at, costs are estimates, and often don’t reflect how long a query runs for…

“Surely this one will get a clustered index scan.”

Last Updated December 7, 2018

Brent Ozar

Execution Plans

I love building demos for our training classes because I’m constantly in a battle of the minds with SQL Server. I try to guess what he’s going to do next, and I love it when he surprises me. I started by building a new parameter sniffing demo with the Stack Overflow database, and in this…

Indexed View Matching With GROUP BY And DISTINCT

Last Updated November 29, 2018

Erik Darling

Execution Plans, Indexing

Bit Of A Kick I’ve been playing with indexed views a little bit lately for some demos in my Bits Precon. There are a whole bunch of limitations in creating indexed views. One of them is that you can’t base the query on DISTINCT. Fair enough, but you can do GROUP BY. And what’s pretty…

Tales From Overindexing: Too Many One Column Indexes

Last Updated November 23, 2018

Erik Darling

Execution Plans, Indexing, SQL Server

Master Plan Sometimes you see a query, and it’s hitting one table, and then the query plan looks like a vase full of spaghetti. Usually, there’s a view involved. Usually. Sometimes, there’s just really weird indexing. Here’s A Thing, Look At It Promises This is a query against one table. No views, no functions, no…

Getting Sneaky With Forced Parameterization

Last Updated November 23, 2018

Erik Darling

Execution Plans

Silly Rules I’ve blogged about some of the silly rules about where Forced Parameterization doesn’t work. One rule that really irked me is this one: The TOP, TABLESAMPLE, HAVING, GROUP BY, ORDER BY, OUTPUT…INTO, or FOR XML clauses of a query. TOP and FOR XML, get used, like, everywhere. TOP is pretty obvious in its usage.…

Not So Forced Parameterization

Last Updated November 26, 2018

Erik Darling

Execution Plans

Asking The Wrong Question Sometimes, when you wanna turn on a feature, you spend so much time wondering if you should, you don’t bother asking if it’ll even work when you do. There are a long list of things that are incompatible with Forced Parameterization, on a page that’s pretty hard to find. Now, there’s…