We All Have It
You know those tables, right? The ones where developers went and got lazy or didn’t know any better and decided every string column was going to be gigantic.
They may have read, of course, that SQL …
Category: Query Tuning
CPU & RAM Don’t Lie: Query Metrics I Care About For Tuning
Discarded
There are metrics that I care and don’t care about when I’m looking for queries to tune.
Metrics I don’t care about:
- Logical Reads
- Costs
If a query does “a lot” of reads or has a high “cost”, I …
Getting Parameter Values From A SQL Server Query Plan For Performance Tuning
Property Management
I’m a really big fan of using operator properties for a lot of things, at least visually. Where things sort of fall down for that is copying and pasting things out.
For some stuff, you still need …
Getting The Top Value Per Group With Multiple Conditions In SQL Server: Row Number vs. Cross Apply With MAX
Throat Music
In yesterday’s post, we compared a simple situation trying to find the post scoring post for each user.
In today’s post, we’re going to add another condition: we want the highest scoring post for each type of post …
Getting The Top Value Per Group In SQL Server: Row Number vs. Cross Apply Performance
Introductions
There are many ways to express queries in SQL. How different rewrites perform will largely be a function of:
- You not doing anything ridiculous
- Queries having good indexes in place
- The optimizer not seeing through your tricks and giving
Software Vendor Mistakes With SQL Server: Dealing With Bad Parameter Sniffing
Bad Wrap
When people hear the words “parameter sniffing”, there’s almost a universally bad reaction. They lose their minds and start raving about how to “fix” it.
- Recompiling everything
- Using optimize for unknown hints
- Using local variables
- Clearing the plan
Software Vendor Mistakes With SQL Server: Writing And Optimizing Paging Queries
Paging Doctor Darling
Words I’ll never hear, at least in reference to me. I’m sure there’s a Darling out there who is a doctor. A real doctor, too. Not one of those “I went to college for 7 extra years” …
Software Vendor Mistakes With SQL Server: Handling Optional Parameters
Optionally Yours
You’ve got tables. So many tables And columns. So many columns.
Users — demanding as they are — might wanna see, search, and order by all sorts of things in those many columns in those many tables. Writing …
Software Vendor Mistakes With SQL Server: IF Branching In Stored Procedures
What Goes Wrong
I still see people calling into this trap when writing stored procedures. What no one seems to realize until it’s too late data grows past a toy data base size, is that SQL Server’s query optimizer doesn’t …
Software Vendor Mistakes With SQL Server: Using Left Joins To Find Rows That Don’t Exist
Natural Language
In SQL Server’s T-SQL, and in the more general ANSI-Standard SQL, you’re supposed to write queries in a way that mimics how you’d ask the same question — just don’t call it a query — in English. Because …