Way Out
Whenever I see people using NOLOCK hints, I try to point out that they’re not a great idea, for various reasons explained in detail all across the internet.
At minimum, I want them to understand that the hint …
Category: Wait Stats
I/O Bound vs CPU Bound Queries
Handcuffed
When you’re looking for queries to tune, it’s important to understand which part is causing the slowdown.
That’s why Actual Execution plans are so valuable in newer versions of SQL Server and SSMS. Getting to see operator timing and …
Wait Stats During Exchange Spills
Inorganic
Lots of people say these are rare — and perhaps they are becoming more so — but I still see them with some frequency. That’s not a terribly strong indictment of SQL Server, but that’s not the point of …
Wait Stats During Hash Spills
Jam Job
Hash spills are, as we’ll see, sometimes identified by a different wait than sort spills. In small quantities, spills are often not worth bothering with. But when they pile up, they can really cause some severe performance issues.…
Wait Stats During Sort Spills
Over Under
Over the next few days, I’m going to look at the wait stats that show up during different types of spills of different sizes. For no reason whatsoever, I’m going to start with sort spills. I’ll also cover …
The Three Kinds Of Memory Contention In SQL Server
Savings and Loans
Whomever decided to give “memory bank” its moniker was wise beyond their years, or maybe they just made a very apt observation: all memory is on loan.
Even in the context we’ll be talking about, when SQL …
Join Me At Data Platform Summit 2020!
The Road From Nowhere
This year, I’m teaching an 8 hour online workshop at Data Platform Summit, and I’d love it if you joined me.
Here’s what I’ll be teaching:
Class Title: The Beginner’s Guide To Advanced Performance Tuning…
Please Stop Filtering CXCONSUMER Out Of Actual Execution Plans
I’m Begging You, Here
Ever since SSMS started collecting wait stats in query plans, I’ve been mad about a couple things that get filtered out:
- Lock waits
- CXCONSUMER waits
Lock waits are particularly annoying. Imagine (I know, this might be …
Reasons Your Query Is Slow Right Now: Blocking, Blocking, Blocking
Lockzilla
Blocking sucks. SQL Server should have used an optimistic isolation level by default.
Sure, writers would still block each other, but think of all the time people could have saved not explaining NOLOCK hints.
- Yes, they still take locks
Reasons Your Query Is Slow Right Now: Your Server Is Overloaded
Oh Baby Another Series
Don’t you love lists? I love lists. They’re so nice and tidy, like a RegEx. Just the other night I was thinking how nice it’d be to write a RegeEx to detect RegEx patterns.
I didn’t …