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Curated SQL Posts

WideWorldImporters Deadlocks

Published 2016-09-14 by Kevin Feasel

Kendra Little has a couple queries to force deadlocks in the WideWorldImporters database:

SQL Server’s deadlock manager woke up, looked around, and saw that our two session windows were stuck. They each were requesting locks that the other session wouldn’t give up– and if the deadlock manager didn’t break the deadlock, they’d be stuck there forever.

I didn’t set the deadlock priority on any of my transactions, so the deadlock manager picked the session that it thought would be the least work to roll back– and it became the victim.

Read on for the scripts and also some hints to help you learn more about deadlocks.

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Paste The Plan

Published 2016-09-14 by Kevin Feasel

Brent Ozar introduces a new website:

It’s a free community service. We hope you love it as much as we do, especially all the cool new execution plan icons by our illustrator, Eric Larsen.

Down the road, we’re thinking about adding logins (so you can see past plans you’ve submitted), execution plan advice, image and HTML downloads (so you can embed the plan in your own blog or report), zooming, and more.

Check out the Paste The Plan website.

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After Triggers On Memory-Optimized Tables

Published 2016-09-14 by Kevin Feasel

David Klee shows that you can put an AFTER trigger on a memory-optimized table in SQL Server 2016:

SQL Server 2016 supports AFTER triggers! I could find no good example of how to do this with a project I’m working on, so I figured out how to make this work. The following before and after screenshots are from a SQL Server 2016 instance and the DVDStore3 package. I modified a trigger to work with In-Memory OLTP.

Click through to see the code.

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Finding Cumulative Updates

Published 2016-09-14 by Kevin Feasel

Jonathan Kehayias shows where to find older cumulative updates:

However, to my dismay that link took me to the download link for SQL Server 2014 SP1 CU8 and not to CU7 as I was expecting. So I tried other SP1 CU links and they all redirect to the CU8 download page. Slightly irritated I decided to send a Skype IM to Glenn (@GlennAlanBerry|Blog) what was going on because he keeps up with every update Microsoft publishes for SQL Server. Glenn told me that Microsoft’s recommendation and preference is for people to install the latest CU so the KB articles now link to the latest CU download page. That doesn’t really help me with adding a failed FCI node back into a FCI that is on CU7, so Glenn offered to share the CU7 file with me by Dropbox.

It turns out that I didn’t need Glenn to share the file with me, I needed to read the information on the KB article closer and pay attention.

Read on to find out where you can find the CU archives.

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Integrating Power BI Into Powerpoint

Published 2016-09-13 by Kevin Feasel

Reza Rad shows how to tell a data story using a combination of Powerpoint and Power BI:

You can see here that I’ve added a title for this slide in Power Point, and also a Textbox with text “Psychology has the most sales”. Yes, with this method you can add commentary to Power BI reports and dashboards, you can tell the story behind the data with integration of Power BI and Power Point. very simple feature but really useful.

Under each Power BI tile in Power Point there will be a link to Power BI

Read the whole thing.

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Securing Elasticsearch And Kibana

Published 2016-09-13 by Kevin Feasel

Vikash Selvin shows how to secure instances of Elasticsearch and Kibana:

The most popular options for securing Elasticsearch and Kibana are compared in the table below.

Shield is a security plugin developed by the same company that developed Elasticsearch. It allows you to easily protect this data with a username and password while simplifying your architecture. Advanced security features like encryption, role-based access control, IP filtering, and auditing are also available when you need them.

NGINX is an open source web server. It can act as a proxy server and can do load balancing, among other things. In combination with LUA and external scripts, it can be used for securing Elasticsearch and Kibana. We will be using this approach in this tutorial.

Searchguard is an open source alternative for Shield. It provides almost all the same functionalities as Shield, except for some features like LDAP authentication. However, these features are available in the paid variant.

Click through for a detailed NGINX setup.

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Shiny 0.14 Released

Published 2016-09-13 by Kevin Feasel

Winston Chang reports that Shiny version 0.14 is now available:

If your Shiny app contains computations that take a long time to complete, a progress bar can improve the user experience by communicating how far along the computation is, and how much is left. Progress bars were added in Shiny 0.10.2. In Shiny 0.14, we’ve changed them to use the notifications system, which gives them a different look.

Important note: If you were already using progress bars and had customized them with your own CSS, you can add the style = "old" argument to yourwithProgress() call (or Progress$new()). This will result in the same appearance as before. You can also call shinyOptions(progress.style = "old") in your app’s server function to make all progress indicators use the old styling.

It looks like they’ve made some good progress with Shiny.

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Administrative Scripts

Published 2016-09-13 by Kevin Feasel

Slava Murygin has ten Powershell scripts to help administer a SQL Server instance:

Script #5. Read SQL Server Error Log file.

That is extremely important troubleshooting script. When you start/restart the SQL Server service and it does not come up, you can run this script to see what was going on during the SQL Server startup and what was the problem (just note that value of “$SQLInstancePath” must be pre-set by previous script):

Click through for all of the scripts.

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Understand Your Testing Utilities

Published 2016-09-13 by Kevin Feasel

David Klee shows an issue with using iperf for load testing:

The load test utility had maxed out the compute resource that it had available, due to internal limitations within iperf itself.  It’s a shame that this utility is not multi-threaded, because I think we could have a much greater result of improvement on this system.

Monitor the utilities that you’re using to do load testing, because limitations like this might skew your results!

Everything eventually hits a bottleneck.  In David’s case, the bottleneck was in the testing tool itself.

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Query Performance Insight

Published 2016-09-13 by Kevin Feasel

Arun Sirpal discusses Query Performance Insight in Azure SQL Databases:

Here you will be presented with the TOP X queries based on CPU, Duration or Execution count. You will have the ability to change the time period of analysis, return 5, 10 or 20 queries using aggregations SUM, MAX or AVG.

So let’s look at what information is provided based on queries with high AVG duration over the last 6 hours.

Looks like an interesting way to get information on the few most heavily used queries.

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