A Fine Slice Of SQL Server
Sebastian Sauer embraces the third dimension:
Here’s the linear model with 2 predictors, giving us a model that can be visualized in 3D:
lm1 <- lm(mpg ~ hp + disp, data = mtcars)As is standard, we’ll predict
mpg.
Click through for a simple implementation using plotly.
Comments closedRobert Cain looks at the search operator in KQL:
In this post we will examine the KQL (Kusto Query Language)
searchoperator. Search allows us to look across all columns in one or more tables for a specific text string.The samples in this post will be run inside the LogAnalytics demo site found at https://aka.ms/LADemo. This demo site has been provided by Microsoft and can be used to learn the Kusto Query Language at no cost to you.
Click through to learn more about this very useful operator.
Comments closedI can imagine someone reading that and not seeing the gravity of the situation. “Hey, 500 rows isn’t that many – we have modern hardware!”
I thought it was worth writing about a real world situation where this can get seriously out of hand.
Read on for a scenario in which 64 rows turns into 100,000 rows pretty quickly.
Comments closedMichael Bourgon notices a difference between Azure SQL DB and Managed Instance/box product:
I was trying to get some Xquery parsing working, and ran into a weird error:
"CONDITIONAL failed because the following SET options have incorrect settings: 'QUOTED_IDENTIFIER'"Weird. Doubly so because this code has worked on-prem for a decade, and the Managed Instance is running it now.
Read on for the solution.
Comments closedChad Callihan looks at buffer pool extension:
Perhaps you started out with X amount of memory when your SQL server was brought online and over time, with additional load and activity on that SQL server, users are not quite getting the type of performance they’re used to getting. Sure, you can buy more memory. What if that’s not an option?
If you’re running low on memory and need a little boost, enabling buffer pool extension can take advantage of an SSD as an “extension” for the buffer pool.
This is one of those interesting features that probably help a small number of customers but shouldn’t be generally useful. That’s because even with SSD performance improvements, memory is still a couple orders of magnitude faster, so as long as you have the ability to increase RAM, that brings much better performance.
Comments closedBob Dorr troubleshoots a performance problem:
When the temporary table is bound to the user transaction it is both created and destroyed as part of the transaction. The same logic in a procedure attempts to avoid the creation and destruction, for each execution, by using temporary table caching.
From the issue I was debugging, the user transaction scope mattered because creation and destruction of metadata may be an expensive operation.
This post ties into two separate things: first, how temp objects tie to specific sessions; and second, the cost of creating and destroying temporary objects. For the latter, a couple quick pieces of advice: