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Author: Kevin Feasel

Fun with tempdb

Published 2020-04-22 by Kevin Feasel

Andy Mallon walks us through setting up tempdb:

There are three problems I’ve got to fix. I need to (1) remove those two extra files, (2) grow the tempdb log file, and (3) even out the size of the data files (and shrink them a little to make room for the larger log file. We’re going to tackle these in the reverse order than I listed them–partially out of necessity, and partially because it’s going to be easier.

Click through to see how Andy sets up tempdb. This is a good way to set up tempdb.

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Tempdb Issues You Might Have

Published 2020-04-22 by Kevin Feasel

Fabiano Amorim walks through a few of the tricky issues around tempdb:

One of many performance improvements that came with SQL Server 2014 is that it doesn’t flush dirty pages created in a minimally logged operation on tempdb. This gives you the benefit of having faster (compared to prior versions) inserts, but it caused another problem as those allocated pages may take a lot of time to be removed from the buffer pool data cache. Before discussing the problem, quickly look at the benefit and then understand some important concepts of flush dirty pages on tempdb.

Click through to learn more about the fix, and then a fix to the fix…which opened up a new avenue to fix. This kind of thing is why operating at scale is so difficult: the solution to one problem often becomes the avenue to a new problem.

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Ownership Chaining in SQL Server

Published 2020-04-22 by Kevin Feasel

K. Brian Kelley walks us through the concept of ownership chaining in SQL Server:

Ownership chaining is a security feature in SQL Server which occurs when all of the following conditions are true:

– A user (which could be an app through a login/service account) tries to access an object that makes a reference to another object. For instance, the user tries to execute a stored procedure that accesses other objects or a SELECT from a view that accesses other tables.
– The user has access to the first object, such as EXECUTE rights on the stored procedure or SELECT rights on the view.
– Both objects have the same owner.

In this case, SQL Server will see the chain between the object the user called and the object being referenced. SQL Server will also determine that the owner for both objects is the same. When those conditions are met, SQL Server will create the ownership chain.

Read on for an in-depth example of ownership chaining and how it solves certain problems around managing database rights.

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Operations Testing with Pester

Published 2020-04-22 by Kevin Feasel

Sheldon Hull takes us through using Pester to automate operations tasks:

In my example, let’s start small and say you just have PowerShell, and some servers.

What I’ve discovered is that to actual validate DevOps oriented work is completed, you typically go through the equivalent of what a Cucumber test would have. This “checklist” of validations is often manually performed, lacking consistency and the ability to scale or repeat with minimal effort.

Consider an alternative approach to helping solve this issue, and expanding your ability to automate the tedious testing and validation of changes made.

Read on for an example as well as some additional thoughts from Sheldon.

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Refreshing Selected Tables in Power BI Desktop

Published 2020-04-22 by Kevin Feasel

Gilbert Quevauvilliers answers one of the great mysteries in life:

When working with Power BI datasets I often want to refresh multiple tables, BUT not all the tables in my model. (This often happens when I made a change to underlying data sources and I want to make sure it is working as expected in Power BI Desktop)

I recently found that I could do it by doing the following steps below.

When you have one or two big tables and you don’t make any changes to those tables, it can be a pain waiting for them to refresh. This is a great alternative.

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Memory Management in Flink 1.10

Published 2020-04-21 by Kevin Feasel

Andrey Zagrebin walks us through some memory management improvements in the most recent version of Apache Flink:

Apache Flink 1.10 comes with significant changes to the memory model of the Task Managers and configuration options for your Flink applications. These recently-introduced changes make Flink more adaptable to all kinds of deployment environments (e.g. Kubernetes, Yarn, Mesos), providing strict control over its memory consumption. In this post, we describe Flink’s memory model, as it stands in Flink 1.10, how to set up and manage memory consumption of your Flink applications and the recent changes the community implemented in the latest Apache Flink release.

Click through to learn about the current model and methods to control memory utilization.

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Getting a Better Windows Terminal

Published 2020-04-21 by Kevin Feasel

Sheldon Hull takes us through the Windows Terminal experience:

I’ve long been a Cmder/ConEmu user for Windows as it’s provided a much-needed improvement of the standard Windows terminal.

I’ve started trying to use the newer Windows Terminal project to benefit from the improved performance and support, and found getting it up and running with any customizations was a little time consuming and confusing. This wasn’t something I’d hand off to someone who wasn’t looking for experimentation.

Click through for a few scripts and screenshots.

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Calculation Groups in Analysis Services and Power BI

Published 2020-04-21 by Kevin Feasel

Kasper de Jonge walks us through calculation groups:

In most cases the business wants to see some common calculations done over these measures like YTD, QTD, YoY% etc. That means you must make a new measure for each of the calculation over the base measure. This leads to measure explosion in your model as you need to add a new measure for each variation. Very quickly this leads to not four measures but sixteen and more creating a management headache.

In come calculation groups. With calculation groups you can create a group that can apply common calculation over base measures. It’s hard to explain so let’s just dive in on how that works.

Click through for a demo of how to enable and use calculation groups.

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Set Comparisons with EXCEPT

Published 2020-04-21 by Kevin Feasel

John Sterrett walks through one of the most important set operators:

Selecting the two tables is easy if we know what change occurred and there aren’t many changes. This can get complicated quickly. Therefore, if we just want to quickly know if we have differences lets take a look at my goto method using EXCEPT. To make this example easier to read instead of using “SELECT *” I will just focus on columns that are changing. In a real example, I would want to know if any columns changed.

One of the nicest things about set comparison operators is that they innately understand the concept of NULL.

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Auditing Logons Using Extended Events

Published 2020-04-21 by Kevin Feasel

Jason Brimhall dumps a server-side trace in favor of extended events:

Some time ago, I wrote an article for SQL Server 2008 to help determine the use of the server since SQL Server 2008 was reaching End Of Life. In that article, I shared a reasonable use of server side trace to capture all of the logon events to the server. Afterall, you have to find out the source of connections and who is using the server if you need to migrate it to a newer SQL Server version. You can read that article here.

Soon after, from various sources, I received requests on how to perform a logon audit using the more preferred, robust, venerable, awesome tool called Extended Events (XEvents). In response, I would share a login audit session to each person. In this article, I will share my login audit solution and give a brief explanation. I use a solution like this on more than 90% of my client servers and I find it highly useful.

Click through to see how.

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