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Day: March 18, 2016

Live Query Stats Versus Actual Execution Plans

Published 2016-03-18 by Kevin Feasel

Kendra Little compares and contrasts Live Query Statistics against actual execution plans:

Getting plan details isn’t free. The amount of impact depends on what the query is doing, but there’s a stiff overhead to collecting actual execution plans and to watching live query statistics.

These tools are great for reproing problems and testing outside of production, but don’t time query performance while you’re using them– you’ll get too much skew.

Live Query Statistics is one additional tool, but won’t replace actual execution plans.  At its best, it will make you think more about what’s going on with the system, whether row counts are what you’re expecting, and take account of which operators stream data through without blocking (such as nested loop joins) versus those which require all the data before continuing (sorts).

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Power BI Auto-Installation

Published 2016-03-18 by Kevin Feasel

Simon Sabin uses Powershell to install Power BI:

Having recently been having rebuilding my machine I finally decided to automate the process of installing the software I need.

This was a life saver as I was reinstalling a few times to try and figure out why I wasn’t getting sound on my external monitor. So I was gradually uninstalling everything until I found out that it was Hyper-v that was causing the problem.

The outcome meant I was installing PowerBI lots and had to automate it.

This looks like the first step toward a Chocolatey script.

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Joining On NULL

Published 2016-03-18 by Kevin Feasel

Erik Darling has opened a can of worms here:

WITH ALL THE TROUBLE NULLS CAUSE…

You’d think people would be more inclined to avoid them. Slap a NOT NULL constraint and a default value on your column and call it a day. I’m perfectly fine with bizarro world canary values. If it’s an integer column, some really high (low?) negative number. If it’s date-based, why not have it be the lowest value your choice accomodates?

Check out the comments, definitely.  I don’t think it’s as clear-cut as Erik argues; the idea of NULL has been and will remain controversial because it’s a useful concept but one which requires explicit consideration.

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SQLPS Update

Published 2016-03-18 by Kevin Feasel

Chrissy LeMaire has an update on SQLPS and SQL Server Linux:

  • Microsoft is investigating options for a cross-platform lightweight SQL Management Studio GUI tool for Linux.

  • Microsoft is investigating open sourcing the SQL Server PowerShell provider and cmdlets, and that it “makes a lot of sense” and “aligns with what Microsoft has already done with our Azure PowerShell cmdlets on github.” This is being tracked by connect item 2442788.

  • Microsoft doesn’t have dates or more details to share for any of these items at this time and will keep the community updated on their progress as they continue to evaluate our plans based on customer feedback

I’m most interested in the first of these points, but this is all interesting news.  Also check out her guest appearance on the PowerScripting Podcast.

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Find Object Dependencies

Published 2016-03-18 by Kevin Feasel

Manoj Pandey has pulled out the code used in Management Studio to get dependencies:

And here is a very lengthy (~900 lines) T-SQL Code that I generated from SSMS & SQL Profiler to check the same Dependencies of a Table in SQL Server 2014. You can also create a Stored Procedure and apply the Table & Schema as parameters.

You can just replace the Table & Schema in the first 2 lines and execute the code to check table dependencies

You might be able to optimize this script, but it’s nice to have a starting point.

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Nested Display Folders

Published 2016-03-18 by Kevin Feasel

Koen Verbeeck shows how to use nested display folders in Analysis Services and get Power BI to use them as well:

On the same day, I also found out it’s possible to nest display folders in SSAS. Which was even better, because I have a project with dozens of measures and this functionality really makes the difference. All you have to do is putting backslashes to indicate where a new child folder begins

This makes intuitive sense, so good on Microsoft for supporting this.

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