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Author: Kevin Feasel

SSIS Firewall Rules

Published 2016-07-20 by Kevin Feasel

Slava Murygin shows how to create a firewall rule to allow SSIS connections:

Recently tried to connect to Remote SQL Server Integration Service directly from SSMS and got following error:

TITLE: Connect to Server
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Cannot connect to 10.1.32.66.
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ADDITIONAL INFORMATION:
Failed to retrieve data for this request. (Microsoft.SqlServer.Management.Sdk.Sfc)
For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft%20SQL%20Server&LinkId=20476
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The RPC server is unavailable. (Exception from HRESULT: 0x800706BA) (Microsoft.SqlServer.DTSRuntimeWrap)
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The RPC server is unavailable. (Exception from HRESULT: 0x800706BA) (Microsoft.SqlServer.DTSRuntimeWrap)
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BUTTONS:
OK
——————————

Slava then shows how to work around this.

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Missing Values In R

Published 2016-07-20 by Kevin Feasel

David Smith explains NA values in R:

Here’s a little puzzle that might shed some light on some apparently confusing behaviour by missing values (NAs) in R:

What is NA^0 in R?

You can get the answer easily by typing at the R command line:

> NA^0
[1] 1

But the interesting question that arises is: why is it 1? Most people might expect that the answer would be NA, like most expressions that include NA. But here’s the trick to understanding this outcome: think of NA not as a number, but as a placeholder for a number that exists, but whose value we don’t know.

Definitely read the comments on this one.

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Diagnosing Memory Grant Issues

Published 2016-07-20 by Kevin Feasel

Pedro Lopes looks at Extended Events around memory grants:

Three conditions can trigger this warning to show up in showplan:

  1. Excessive Grant: when max used memory is too small compared to the granted memory. This scenario can cause blocking and less efficient usage when large grants exist and a fraction of that memory was used.

  2. Used More Than Granted: when the max used memory exceeds the granted memory. This scenario can cause OOM conditions on the server.

  3. Grant Increase: when the dynamic grant starts to increase too much, based on the ratio between the max used memory and initial request memory. This scenario can cause server instability and unpredictable workload performance.

I like that this information also shows up when you view an execution plan using SSMS 2014 SP2.

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Deprecated SSAS Features

Published 2016-07-20 by Kevin Feasel

Chris Webb looks at Analysis Services functionality deprecated (or discontinued) as of 2016:

Some time ago I blogged about the deprecated and discontinued functionality in SSAS 2014, so I thought it would be a good idea to follow my last post on what’s new in SSAS 2016 Multidimensional with a discussion of what’s going or gone from it.

The same page that I linked to last time has been updated for 2016, and there are four more subpages with all the details. There’s nothing much interesting to say about the breaking changes (basically AMO has been rejigged) or behaviour changes (there’s no in-place upgrade for Tabular models using DirectQuery – you have to open the project and edit some settings) but the other two pages do have some news worthy of comment:

It looks like there are some potentially interesting features on the chopping block.  My Analysis Services experience is extremely limited, so I’ve never used any of them, but looks like it might be worth checking out if you have production cubes.

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SQL Server’s Basic Installer

Published 2016-07-20 by Kevin Feasel

Derik Hammer walks through the new SQL Server Basic Installer:

When using the Basic Installer only the database engine and SQL Client Connectivity SDK are installed. I find this better than using the advanced installer’s Install with all defaults option. Typically any local user will not need Reporting Services, Integration Services, Analysis Services, or any other feature available.

I was a bit concerned about this when it was first announced—the default installer already allows you to make too many poor decisions—but I think it works within the use case Derik describes:  developers installing a local edition on their dev boxes.

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Understanding Spark APIs

Published 2016-07-19 by Kevin Feasel

Jules Damji explains when to use RDDs, when to use DataFrames, and when to use Datasets in Spark:

Like an RDD, a DataFrame is an immutable distributed collection of data. Unlike an RDD, data is organized into named columns, like a table in a relational database. Designed to make large data sets processing even easier, DataFrame allows developers to impose a structure onto a distributed collection of data, allowing higher-level abstraction; it provides a domain specific language API to manipulate your distributed data; and makes Spark accessible to a wider audience, beyond specialized data engineers.

With Spark 2.0, the balance moves in favor of the more structured data types.  What’s old is new; what’s unstructured is structured…

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Pay Attention To Benefits

Published 2016-07-19 by Kevin Feasel

Andy Mallon discusses the importance of benefits:

I honestly believe that company benefits tell you more about a company than any formal interview will. The benefits that a company offers to an employee are a sign of how you’ll be treated if you work there. There is definitely a correlation between great benefits and happy employees.

Companies who respect their employees will express that respect through their benefits. (The inverse is also true–companies often have poor benefits because they do not respect their employees.)

Employment is a package deal, so if you’re not paying attention to benefits, you’re missing part of your bottom line.

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Generating Change Scripts

Published 2016-07-19 by Kevin Feasel

Steve Jones shows off a rather valuable feature in SQL Server Management Studio:

One of the really basic things I think everyone should understand is how to get scripts from Management Studio (SSMS) and saving them. In fact, I’ve written that everyone should use this button and really not ever execute their GUI changes. Capture the script, save that, and automate things.

However, that’s not what this post is about. This post is about how you get a script to look at changes, or better understand how SSMS might implement your changes.

The ability to script out your changes has a number of benefits, one of which is that you’ll get to learn the code you need to write to perform an action, which could make all the difference in a production-down situation.

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Why Learn Scala?

Published 2016-07-19 by Kevin Feasel

Kevin Jacobs explains why Scala is a useful language:

Is it a functional programming language? Is it an object-oriented programming language? The answer to both questions is yes! Scala is a object-functional programming language. The good old well-known stuff is all in Scala. You can build complex applications by the means of objects and classes. On the other hand, Scala tries to teach programmers a paradigm called functional programming. In functional programming, a computation is treated as the evaluation of a mathematical function. So in that sense, everything in Scala is an evaluation. You might wonder why you would ever need functional programming if you are used to object-oriented programming. Well, the case is that in imperative programming you are changing the state over and over again. This is not allowed in functional programming. The changing of the state causes side-effects and makes your application less transparent. A imperative application is therefore often hard to debug while a functional program is easy to debug since it does not change the state. A concrete example is given below

Scala is to Java as F# is to C#.

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Common Table Expressions Aren’t Tables

Published 2016-07-19 by Kevin Feasel

Grant Fritchey shows that CTEs are not tables; they’re expressions:

The Common Table Expression (CTE) is a great tool in T-SQL. The CTE provides a mechanism to define a query that can be easily reused over and over within another query. The CTE also provides a mechanism for recursion which, though a little dangerous and overused, is extremely handy for certain types of queries. However, the CTE has a very unfortunate name. Over and over I’ve had to walk people back from the “Table” in Common Table Expression. The CTE is just a query. It’s not a table. It’s not providing a temporary storage space like a table variable or a temporary table. It’s just a query. Think of it more like a temporary view, which is also just a query.

Read the whole thing.

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