Work It
Memory is S-Tier crucial for most workloads to run reliably fast. It’s where SQL Server caches data pages, and it’s what it gives to queries to process Sorts and Hashes (among other things, but these are most common).…
Category: Wait Stats
Why Some Types of Parallel Scans can be Slow on Cloud Storage
Upon reading the title, you may be thinking that of course parallel scans will be slow in the cloud. Cloud storage storage simply isn’t very fast. I would argue that there’s a bit more to it.
The Timeout
A query …
Signs You Need More Memory In Your SQL Server
Guessotron
Most of these signs have to do with wait stats. One could venture out and say that if you have way less memory than data, you need more memory, but… If the server is sitting around bored, who cares?…
Signs You Need Batch Mode To Make Your SQL Server Queries Faster
My Name Is
I speak with a lot of DBAs and developers who have either heard nothing about column store and batch mode, or they’ve only heard the bare minimum and aren’t sure where it can help them.
Here’s a …
SQL Server Features I Still Need To Talk People Into Using
Booze Schmooze
As a counterpart to yesterday’s post, I have a list of Great Ideas™ that sometimes it’s hard to get people on board with, for some reason.
Don’t get me wrong, some people can’t jump on this stuff fast …
My SQL Server Query Ran For A Long Time But Didn’t Use A Lot Of CPU: What Happened?
Of Walls And Clocks
No one ever says a broken record is right twice a day, perhaps because DJs are far more replaceable than clock makers.
I say that only to acknowledge that I may sound like a broken record …
Steps For Getting Rid Of NOLOCK Hints In SQL Server Queries
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 …
I/O Bound vs CPU Bound Queries In SQL Server
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 In SQL Server Parallel Query Plans
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 In SQL Server Query Plans
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.…