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Author: Kevin Feasel

Data Flow Sequence Containers

Published 2016-12-06 by Kevin Feasel

Todd McDermid is excited about data flow groups in Integration Services:

Data Flow Groups

Data Flow Groups is what they’re calling it, and it’s deceptively simple to use.  One of the reasons I’m sure I (and SSIS people I talk to who DID NOT LET ME KNOW IT WAS THERE) missed it is because I was expecting it to be a component in the toolbox.  Not so.
Code up your Data Flow as you normally would.  Then go and select the components that you want to group together – via clicking and dragging a selection window, or click-selecting components.  Any component combinations you want.  Then right-click and select Group.

I admit that I didn’t know it existed either.  This does seem rather useful.

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Multivariate Analysis In R

Published 2016-12-06 by Kevin Feasel

Mala Mahadevan looks at using R to describe data sets with two explanatory variables:

From the plot we can see that type 3 trees have the smallest circumference while type 4 have the largest, with type 2 close to type 4. We can also see that type 1 trees have the thinnest dispersion of circumference while type 4 has the highest, closely followed by type 2.  We can also see that there are no significant outliers in this data.

Understanding whether variables are categorical or continuous is vital to understanding what you can and should do with them.

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Custom Functions In Power BI Desktop

Published 2016-12-06 by Kevin Feasel

Reza Rad explains custom functions:

Benefits of Custom Function

  • Re-Use of Code
  • Increasing Consistency
  • Reducing Redundancy

With a Custom function you are able to re-use a query multiple times. If you want to change part of it, there is only one place to make that change, instead of multiple copies of that. You can call this function from everywhere in your code. and you are reducing redundant steps which normally causes extra maintenance of the code.

I like Reza’s example of reading from a holidays table, as it’s easy enough to follow without being so trivial that it leaves you to wonder what the real value is.

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SQL Server Easy Button

Published 2016-12-05 by Kevin Feasel

Drew Furgiuele has an easy button for SQL Server:

Sounds great, right? I bet some of you already already thinking “Oh man, I can’t wait to run the Linux version SQL Server on this thing!” There’s just one really big catch: the CPUs on Pi boards are ARM-architecture based. Unlike modern processors in our desktops and laptops, these chips are more akin to what you find in mobile phones or other small devices. It also means programs you run or write on your computer are probably 32 or 64 bit and designed for Intel or AMD processors. ARM is a completely different architecture, so we can’t upload something to it and expect it to run. Programs have to be designed for it.

Furthermore a lot of “stock” Pi operating system images are Linux based so it can be difficult to write code that interfaces with .NET or Windows-based services. Not that you can’t; you can certainly write bash scripts that make wget or curl requests.

Based on my experiences at least, nothing with Windows IoT was really that easy…  This is an intro post with a shopping list attached, so I am looking forward to Drew’s making everybody’s lives easier on a budget of $98.

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SARGability And Date Math

Published 2016-12-05 by Kevin Feasel

Erik Darling explains performance ramifications of date math operations:

Both plans are helped by our thoughtfully named index on the OrderDate column, though the one with cheaper estimated cost is the bottom one. Yes, I know this can sometimes lie, but we’re not hiding any functions in here that would throw things off horribly. If you’re concerned about the Nested Loops join, don’t worry too much. There is a tipping point where the Constant Scan operator is removed in favor of just index access. I didn’t inflate this table to find exact row counts for that, but I’ve seen it at work elsewhere. And, yeah, the second query will still be cheaper even if it also scans.

Which side of the equation you put a function on can make all the difference.

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Identity Not Found

Published 2016-12-05 by Kevin Feasel

Melissa Coates explains Azure Active Directory tenancy to solve an Azure Analysis Services error:

The Analysis Services product team explained to me that a a user from a tenant which has never provisioned Azure Analysis Services cannot be added to another tenant’s provisioned server. Put another way, our Corporate tenant had never provisioned AAS so the Development tenant could not do so via cross-tenant guest security.

One resolution for this is to provision an AAS server in a subscription associated with the Corporate tenant, and then immediately delete the service from the Corporate tenant. Doing that initial provisioning will do the magic behind the scenes and allow the tenant to be known to Azure Analysis Services. Then we can proceed to provision it for real in the Development tenant.

Read the whole thing.

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Lists And Ranges In Powershell And T-SQL

Published 2016-12-05 by Kevin Feasel

Phil Factor has an interesting post on lists and ranges in two languages:

When a  list like ‘1,3,5,6,9’, or ’12 Jan 2016,14 Jan 2016, 18 Feb 2016’  contains a datatype that can be unambiguously sorted in the order of the values of the datatype, it becomes possible to imply a range. This will trim unwieldy lists significantly if they have a lot of contiguous values.  ‘1,2,3,4,5’ can be expressed as 1-5 (or 1..5). The starting integer is separated from the end integer in the range by a dash sign. This representation rather clashes with the minus sign, represented by the same symbol, but the comma removes the ambiguity. A number followed immediately by a ‘-‘ means that the ‘-‘is a range symbol.  As with SQL’s BETWEEN clause that selects rows, the range includes all the integers in the interval including both endpoints. Because the range syntax is intended to be a more compact form,  it is generally only used where there are at least three contiguous values.

Interesting article.  I recommend checking it out.

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Powershell Runspaces

Published 2016-12-05 by Kevin Feasel

Chrissy LeMaire has a pair of posts on runspaces.  First, a post which includes a runspace template:

Runspaces can be intimidating. I had heard about them, took a look at the code and was like “Ah, that looks complex. I’ll learn that later.” Because of this, I repeatedly went over the bulk insert code to familiarize the audience with the functionality that I was eventually going to multi-thread.

Then she shows us how to output results without waiting for all runspaces to complete:

Recently, I had a request to add multi-threading to Read-DbaBackupHeader. This was the first runspace in which I had to output the results from the runspace to the host — usually I just needed commands to run in the background, like with bulk-inserts to SQL Server.

Runspaces seems to be a good option in Powershell for multithreading.

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Powershell Remoting To Linux

Published 2016-12-05 by Kevin Feasel

Max Trinidad shows that Powershell remoting works for connecting Linux to Windows and vice versa:

Connecting Linux to Windows

This is strange but, more likely, you will get an error the first time you try to connect. Just try the second try and it will work.

I need to see what Powershell objects for Linux currently exist; my guess is “not many, if any” but as those start getting fleshed out, I think even the most adamant of grep-sed-awk users will want to pick up at least a little bit of Powershell.

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