Detained
Despite the many metric tons of blog posts warning people about this stuff, I still see many local variables and optimize for unknown hints. As a solution to parameter sniffing, it’s probably the best choice 1/1000th of the time. …
Category: Query Tuning
UDF Inlining And String Aggregations
Quatro Enemigos
This post is really four different posts. Maybe five. The main points are:
- STRING_AGG can’t be inlined if a UDF
- Getting DISTINCT values into STRING_AGG is more obtuse than it should be
- The documentation for UDF inlining is
Steps For Getting Rid Of NOLOCK Hints
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 …
Signs It’s Time To Switch From ORMs To Stored Procedures
Meet Wall
There are, unfortunately, some times when developers refuse to put the ORM down.
I mean, it’s mostly unfortunate for them, because they’ll continue to have performance problems.
Me? I’ll be okay.
The items in this post are issues …
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 …
Why You Should Stop Looking At Query Cost
Spare No Expense
Over the years, there have been a lot of requests to get sp_BlitzCache to sort results by query cost. I understand why. It’s assumed that the optimizer is never wrong and that cost is directly associated with …
A Parameterization Puzzle With TOP PERCENT
Lawdy
There was a three-part series of posts where I talked about a weird performance issue you can hit with parameterized top. While doing some query tuning for a client recently, I ran across a funny scenario where they were …
How Useful Is Column Store In Standard Edition?
Speed Limit
When I’m blogging about performance tuning, most of it is from the perspective of Enterprise Edition. That’s where you need to be if you’re serious about getting SQL Server to go as fast as possible. Between the unrealistic …
A Useful Rewrite Using APPLY
More To The Matter
In the year 950 B.C., Craig Freedman write a post about subqueries in CASE expressions. It’s amazing how relevant so much of this stuff stays.
In today’s post, we’re going to look at a slightly …