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Author: Kevin Feasel

Simplified Order Of Operations

Published 2016-07-22 by Kevin Feasel

Michael J. Swart looks at how SQL Server implements order of operations:

I have a book on my shelf called Practical C Programming published by O’Reilly (the cow book) by Steve Oualline. I still love it today because although I don’t code in C any longer, the book remains a great example of good technical writing.

That book has some relevance to SQL today. Instead of memorizing the full list of operators and their precedence, Steve gives a practical subset:

    1. * (Multiply), / (Division)
    2. + (Add), – (Subtract)

Put parentheses around everything else.

Parentheses, even when unnecessary, are usually a good idea.  They help the reader understand what was going through your mind at the time.

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New DBATools Cmdlet

Published 2016-07-22 by Kevin Feasel

Rob Sewell describes his experience creating a new cmdlet:

The journey to Remove-SQLDatabaseSafely started with William Durkin b | t who presented to the SQL South West User Group  (You can get his slides here)

Following that session  I wrote a Powershell Script to gather information about the last used date for databases which I blogged about here and then a T-SQL script to take a final backup and create a SQL Agent Job to restore from that back up which I blogged about here The team have used this solution (updated to load the DBA Database and a report instead of using Excel) ever since and it proved invaluable when a read-only database was dropped and could quickly and easily be restored with no fuss.

This is a combination of describing what the cmdlet does as well as the circumstances behind its creation.  It’s a good read.

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HBase Incremental Backup And Restore

Published 2016-07-21 by Kevin Feasel

Carter Shanklin and Vladimir Rodionov discuss incremental backup and restore coming to HBase & Phoenix:

If your tables are large it may not be possible to restore them under a different name due to space constraints. The really powerful thing about HBase backups is they are stored in WAL files that can be parsed using a simple interface that can be consumed either in Java or using the “hbase wal” utility.

Consider this scenario: A customer rep deleted some data because he thought it was unimportant. A week later the customer is upset because the data was important and you need to restore these few pieces of information. With HBase backups all you need to do is parse through the backups with a WAL reader and extract the historical values, which you can then add back in. With other databases you would have to bring another database instance online and load the backups into it. Having backups in open, well-understood formats unlocks many powerful opportunities and can bring recovery times down from days to minutes.

Read on if you manage a Hadoop cluster with HBase (or you’re likely to administer one soon).

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Satellite Image Combination

Published 2016-07-21 by Kevin Feasel

David Yanofsky discusses how he pieced together satellite images for a report on mainland Chinese trash washing up on Hong Kong shores:

The USGS has a website called EarthExplorer that lets you search through decades of satellite data. I limited my search to Landsat 8 data with less than 10% cloud cover.

(you can do this search on the command line with landsat-util too but i prefer the web interface. In the future I will probably use this online toolfrom Development Seed)

Hat tip to Nathan Yau.

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SparkR + Zeppelin

Published 2016-07-21 by Kevin Feasel

I take a look at using SparkR and Zeppelin:

My goal is to do some of the things that I did in my Touching on Advanced Topics post.  Originally, I wanted to replicate that analysis in its entirety using Zeppelin, but this proved to be pretty difficult, for reasons that I mention below.  As a result, I was only able to do some—but not all—of the anticipated work.  I think a more seasoned R / SparkR practitioner could do what I wanted, but that’s not me, at least not today.

With that in mind, let’s start messing around.

SparkR is a bit of a mindset change from traditional R.

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Biml Transformers

Published 2016-07-21 by Kevin Feasel

Bill Fellows uses a Biml transformer to change a variable’s value:

Our transformer is simple. We’ve specified “LocalMerge” as we only want to fix the one thing. That one thing, is an SSIS Variable named “ServerName”.

What is going to happen is that we will redeclare the variable, this time we will specify a value of “SQLQA” for our Value. Additionally, I’m going to add a Description to my Variable and preserve the original value. The TargetNode object has a lot of power to it as we’ll see over this series of posts on Biml Transformers.

I’ve not used transformers before; this was interesting.

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Listing Enterprise-Only Features

Published 2016-07-21 by Kevin Feasel

Patrick LeBlanc has an embedded report which shows Enterprise Edition-only features:

Someone recently asked me if there was a list of all the SQL Server “Enterprise Only” features available on the web.  I pointed them to the Features Supported by the Editions of SQL Server web page and thought I was done.  He stated that this site was good, but did not provide a simple list of enterprise only features.  I thought for a second, and my thoughts went straight to Power BI.  Why?  Simple, there are tables on the web page, and Power BI can easily extract that data into a data model.  I am not going to go into all those details in this blog post.  Maybe one day, but for now take a look at this interactive Power BI report and let me know what you think.

I think this layout is a bit easier to read and follow than the features website, although I’d love to be able to click on an item and get more information on the feature.

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Deployment As Process

Published 2016-07-21 by Kevin Feasel

Ginger Grant argues in favor of deployment processes:

All sorts of things can happen when one person writes and deploys. I know someone who worked in the IT department for a large cell phone company. At the time, working there meant free phone service. One of the devs was a heavy user of the free phone service and so was his large extended family. His job was to maintain the billing code. After several questionable incidents at work, HR got involved and he was perp walked out of the building. Due to the circumstances surrounding his departure, his cell phone accounts were checked to ensure from this point on, he would get a bill. Although his account showed a number of active phones, his balance was always zero. The code in source control was checked and there was nothing in it which provided a reason why his bill was zero. Upon further investigation, my friend noticed the version number in production did not match the version number in source control. The code in source control was compiled and a huge balance appeared for the former employee. If someone else had deployed the code in source control, this chicanery would not have been possible.

This is an interesting read, so go check it out.

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Slack T-SQL Reference App

Published 2016-07-21 by Kevin Feasel

Daniel Hutmacher has a new app to pull MSDN help into Slack:

The API has to do two things: perform an OAUTH authentication, and respond to API queries. Slack uses OAUTH to authenticate that a user really does want to add the app to the Slack team. In essence, this happens in three steps. Slack sends a web request to your API, the API server then requests an OAUTH token from the Slack service (using a secret key), and finally returns this token on the original Slack connection.

As for serving up the T-SQL reference documentation, it’s just a matter of opening static text files in the web server directory and passing them with some encoding to the client. That’s it.

All of these exchanges are JSON encoded, which is trivial to work with in node.js.

If you’re spending all day in Slack, this seems like a pretty good thing to do.

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T-SQL Tuesday Roundup

Published 2016-07-21 by Kevin Feasel

Chris Yates provides a round-up for the latest T-SQL Tuesday:

The roundup is finally here, and cheers to all of you who participated. We had a great turnout this month with many returning participants along with some newcomers.

We had a wide range of topics with many great insights from everyone, but don’t take my word for it. Check out the links below and see what your colleagues from around the SQL Community had to say:

Click through for the links.

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