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Day: July 18, 2019

Bar Chart Presentation Options

Published 2019-07-18 by Kevin Feasel

Andy Kirk gives us five techniques for gussying up bar charts:

“Bar charts are boring”, say many people. “How can we make them more attractive”, say many desperate clients. Bar charts are ubiquitous because they are the reliable and trusted lieutenants often relied upon to show the always-common quantitative comparisons across different categories. Their frequent use can induce ‘boredom’ through the familiar but, in particular, accusations of inelegance can be raised with the default tool styles many creators lean on.

The five charts below just offer some different ways you might style them, through variations in the use of functional colour properties, chart apparatus and layout decisions, in particular. The reasons why you would choose to use any of these methods are varied and especially contextually dependent, based on matters like space to work in, range of quantitative values, size of category labels, number of bars, importance of precise readability. The charts are all showing the all-time top 10 most streamed songs on Spotify, as of July 2019, with data from wikipedia.

Read on for the five options.

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Powershell Modules Everywhere

Published 2019-07-18 by Kevin Feasel

Kevin Chant has some thoughts on whether you should have SQL Server Powershell modules on every server:

Recently I’ve seen recommendations about putting PowerShell modules on every SQL Server. I must admit it has got me thinking if this is indeed worthwhile.

In addition, it makes me wonder if it’s actually better to put the Powershell modules on a select number of management servers instead?

If you are wondering which modules I could be talking about, I mention some in a previous post which you can read in detail here.

Read on for Kevin’s thoughts on the matter.

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Reinforcement Learning with R

Published 2019-07-18 by Kevin Feasel

Holger von Jouanne-Diedrich takes us through concepts in reinforcement learning:

At the core this can be stated as the problem a gambler has who wants to play a one-armed bandit: if there are several machines with different winning probabilities (a so-called multi-armed bandit problem) the question the gambler faces is: which machine to play? He could “exploit” one machine or “explore” different machines. So what is the best strategy given a limited amount of time… and money?

There are two extreme cases: no exploration, i.e. playing only one randomly chosen bandit, or no exploitation, i.e. playing all bandits randomly – so obviously we need some middle ground between those two extremes. We have to start with one randomly chosen bandit, try different ones after that and compare the results. So in the simplest case the first variable e=0.1 is the probability rate with which to switch to a random bandit – or to stick with the best bandit found so far.

Click through for various cases and a pathfinding example in R. H/T R-Bloggers

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Table Variables and Parallelism

Published 2019-07-18 by Kevin Feasel

Erik Darling shows off a neat trick for inserting with parallelism into a table variable:

One of the many current downsides of @table variables is that modifying them inhibits parallelism, which is a problem #temp tables don’t have.

While updating and deleting from @table variables is fairly rare (I’ve seen it, but not too often), you at minimum need an insert to put some data in there.

No matter how big, bad, ugly, or costly your insert statement is, SQL Server can’t parallelize it.

That’s just what he wants you to think and then the trap goes off.

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Changing Query Store Report Interval

Published 2019-07-18 by Kevin Feasel

Arun Sirpal wants to change the report interval for a Query Store report:

While not specific to SQL Server 2019 (I was using this version to do some testing) I was struggling to find how to change the time period of analysis for the Query Store reports within SSMS.

This is not a ground breaking post but hopefully a helpful one! So, I load up the “Top 25 resource consumers” report and by default it will show data for the past hour. So what do you do, or should I say what do you click to change the time interval for the report?

Read on for the two screenshots which answer this question for you.

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T-SQL Tuesday 116 Roundup

Published 2019-07-18 by Kevin Feasel

Tracy Boggiano hosted this month’s T-SQL Tuesday, on the topic of SQL Server on Linux:

I noticed a common theme in how easy it is to install SQL on Linux that tells me if you didn’t think you had time to install SQL on Linux then you probably do and should give a try in the near future.

Thanks for all that participated!

Let me put it this way: one of my employees, who had never really worked with SQL Server before, got SQL Server on Linux installed through Docker in about 15 minutes. It’s really easy to do.

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Power Query FILTER()

Published 2019-07-18 by Kevin Feasel

Rob Collie takes us through a good use of FILTER() in DAX:

The thing both of those formulas have in common is that they are using a measure in the filter argument of the CALCULATE function.  In both examples here, I’ve highlighted the offending measure in yellow.

CALCULATE([Sightings per Year], [Avg Sighting Length in Mins]>6)

CALCULATE([Sightings per Year],
Observations[TTL Min]>[Avg Sighting Length in Mins])

In the first formula, I was trying to use a measure on the left side of the comparison, and in the second, I was trying to use a measure on the right side of the comparison.  Both are illegal.

Read on to see why and how you can use FILTER() to solve these problems.

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