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Author: Kevin Feasel

Kerberos Constrained Delegation On Power BI Report Server

Published 2017-06-01 by Kevin Feasel

Regis Baccaro shows how to set up constrained delegation when connecting Power BI Report Server to a SQL Server instance or Analysis Services cube:

In many demo cases, you will have an all-in-one server where you have installed Power BI Report Server, SSAS (tabular or multidimensional) and SQL Server. In those cases you don’t need any form for credentials delegation since the Report Server is on the same box than the data source.

But there are scenarios where you have a distributed environment like the one I have on my VMs demo domain and for jumping around servers and passing credentials around, you need to setup Kerberos Constrained Delegation. Furthermore you will need protocol transition for it to work in Power BI Report Server.

Read on for step-by-step instructions showing how to do this.

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Troubleshooting Distributed Replay Errors

Published 2017-06-01 by Kevin Feasel

Jonathan Kehayias walks through some common Distributed Replay errors and how to solve them:

On the Distributed Replay Controller machine, permissions need to be set in Component Services to allow the Distributed Replay Client Service accounts Launch and Activate permissions remotely on the COM component. The service accounts also need to be in the Distributed COM Users group in Windows. So in Component Services, expand Computers > My Computer > DCOM Config > DReplayController and right-click and open the Properties for the COM Component.

A lot of this boils down to permissions, but the error messages are about as unhelpful as they get.

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Building Newlines In SQL Scripts

Published 2017-06-01 by Kevin Feasel

Shane O’Neill engages in wacky newline misadventures:

GO is a special little guy. It’s not exactly T-SQL. It’s a way of telling the SQL Server Management Studio (SSMS) to send everything before it, from the beginning of the script or the preceding GO, to the SQL Server instance.

If you read the documents, the main point to take away is…

A Transact-SQL statement cannot occupy the same line as a GO command. However, the line can contain comments.

The problem turns out to be a little trickier than you’d first imagine.  Also, after reading this post, I think it’s lunchtime…

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Memory Requirements For Columnstore Rebuild/Reorg

Published 2017-06-01 by Kevin Feasel

Niko Neugebauer looks at memory requirements for rebuilding and reorganizing columnstore indexes:

To spare all the Wows & how can’s, Microsoft was well aware of this problem and has delivered a solution with Cumulative Update 3 for SQL Server 2016 with Service Pack 1:
FIX: SQL Server 2016 consumes more memory when you reorganize a columnstore index, and here it is – a new trace flag 6404 (documented in the link and thus should be supported), that will allow you to lower the memory requirements for the ALTER INDEX … REORGANIZE command.
Let’s take it for the test, by once again running the setup workload for the FactOnlineSales_Reindex table and then executing the following command, enabling the Trace Flag 6404 and then reorganising our Clustered Columnstore Index:

This is a rather interesting post and once again makes me wish that clustered columnstore indexes could be rebuilt online.

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Side Effects Of Selects

Published 2017-06-01 by Kevin Feasel

Paul Randal describes a few things that can change behind the scenes when you run a SELECT query:

Statistics Update

If the database property Auto Update Statistics is set to True, when a query is being compiled and a necessary statistic is determined to be out-of-date, it will be automatically updated before optimization continues, thus changing the database. Your SELECT statement could cause this to happen. Additionally, if the Auto Update Statistics Asynchronously property is enabled, the statistic will be automatically updated, but after the optimization process (so the compiling query doesn’t have to wait).

Read on for a few more activities.

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Trace Flags Used With Query Store

Published 2017-06-01 by Kevin Feasel

Erin Stellato describes two Query Store trace flags:

Microsoft maintains a list of supported trace flags and I noticed that there are two new ones related to Query Store: 7745 and 7752.  The descriptions for these Query Store Trace Flags are pretty straight-forward, but for those of you not familiar with Query Store, I thought I’d provide some context and details.

Click through for the descriptions of these two trace flags.

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Using sparklyr

Published 2017-05-31 by Kevin Feasel

Hossein Falaki and Xiangrui Meng show how to use sparklyr on a Databricks Spark cluster:

We collaborated with our friends at RStudio to enable sparklyr to seamlessly work in Databricks clusters. Starting with sparklyr version 0.6, there is a new connection method in sparklyr: databricks. When calling spark_connect(method = "databricks") in a Databricks R Notebook, sparklyr will connect to the spark cluster of that notebook. As this cluster is fully managed, you do not need to specify any other information such as version, SPARK_HOME, etc.

I’d lean toward sparklyr over SparkR because of the former’s tidyverse-centric view.

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Play Axis Custom Visual

Published 2017-05-31 by Kevin Feasel

Devin Knight continues his Power BI custom visuals series:

In this module you will learn how to use the Play Axis Power BI Custom Visual.  The Play Axis visual works like a dynamic slicer that animates your other report visuals without needing to click every time you want to change your filter value.

This is a valuable custom visual when dealing with time series data, but as Devin shows, you can iterate through other sets, like a set of employee names.

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Linux Administrative Basics For The SQL Server DBA

Published 2017-05-31 by Kevin Feasel

David Klee continues his SQL Server on Linux series with a discussion of basic Linux installation and usage:

You’ll want to learn the syntax for one of the console-based text editors. My personal favorite is ‘vi‘. It’s quick, streamlined, but does have a significant learning curve. Emacs is another editor that works great. Many others are out there, and your options open even more if you’re using a GUI. You’ll need an editor to edit configuration files.

The folder structure of Linux is one of the biggest changes. Whereas Windows is based off of an arbitrary drive-letter assignment system that dates back to the DOS era, Linux is is based off of a tree structure. All folders and files are based on a single point, ‘/’ or the root folder, and everything is based off of folders from this point. Certain folders from Windows, such as C:\Windows, C:\Users\username, or %WINDOWSTEMP%, are mapped to certain folders within the Linux operating system.

This is really high-level stuff; if you’re looking at administering a Linux box in a production environment, I’d highly recommend taking the time to learn Linux in detail.

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