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Curated SQL Posts

Filtered XML Deadlock Reports with Extended Events

Published 2022-07-15 by Kevin Feasel

Grant Fritchey digs into a useful Extended Event:

One of my favorite little bits of information about Extended Events is the fact that everyone running a full instance of SQL Server has deadlock information available to them, even if they never enabled Trace Flag 1222 through the system_health session. That captures the xml_deadlock_report which has the full deadlock graph. However, what if you want to capture deadlock info, but, you’re dealing the GDPR, and transmitting query values could be problematic? Enter xml_deadlock_report_filtered.

Read on to see how it works, though note Grant’s warning that this is a non-documented event.

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Have One Data Model per Business Area

Published 2022-07-15 by Kevin Feasel

James McGillivray offers us an important piece of advice:

I cannot stress this enough. If people are consuming your data in multiple places, the data needs to come from the same data model. That can be an Enterprise Data Warehouse, a Data Mart, a Power BI Model, or any other data source, but at some point you need to be able to track the data back to a single place. If you don’t do this, you will spend THE REST OF YOUR DAYS explaining the differences between the data models to business and customers, and reconciling the differences over and over again.

Read on to learn why this is so important.

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Saving DateOnly and TimeOnly to Databases

Published 2022-07-14 by Kevin Feasel

Hasan Savran gives us some mixed news:

DateOnly and TimeOnly are the new members of .NET family, they are introduced in version 6. Developers have been asking to declare only a date or only a time without using the DateTime object for a long time. These two new functions will make the developer’s life easy for sure. You can declare them easily but saving them to a database can be a challenge. Before we go into those details for saving them, Let’s look at how to declare and use them in the code.

But right now, they aren’t so useful for SQL Server. Which is a shame, as there are obvious mapping candidates : DATE and TIME, respectively. My hope is that the Microsoft.Data.SqlClient library gets an update pretty soon to handle them. But read on to learn how Cosmos DB handles these new types.

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The ago() Function in KQL

Published 2022-07-14 by Kevin Feasel

Robert Cain continues a series on learning the Kusto Query Language:

The ago function is very similar to the now function, which was discussed in my previous post Fun With KQL – Now. In this article we’ll take a look at ago, see how it works and how it differs from now.

We’ll be using both the print operator and the now function in this post, so if you aren’t familiar with them please go read my articles Fun With KQL – Print and Fun With KQL – Now.

Click through for proper use of ago().

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Giving Managers Access to Servers

Published 2022-07-14 by Kevin Feasel

Tracy Boggiano opens a can of worms:

So, what to rant about?  Should your managers have access to your SQL Server instances? It depends.  You say on what.  Well, just one thing.  What type of manager do you have?

Read on for Tracy’s thoughts on the matter. Speaking as a manager, I tend to agree. If you don’t know what you’re doing, better not to have the ability to mess things up. I can think of oddball scenarios where you might still want the manager to have (at least theoretical) access to a system, primarily as a backstop in case the line staff get locked out or someone gets hit by the lottery bus and you suddenly need to bring in a new employee. That’s more of “break glass in case of emergency” access, though.

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Hardware and Finger-Pointing

Published 2022-07-14 by Kevin Feasel

Glenn Berry gives us two rants for the price of one:

This is rant #1. Even though I have an unusual fascination with computer hardware, I am still somewhat taken aback when I encounter DBAs who have absolutely no idea what type of hardware they are using. I’ll sometimes ask a DBA “What processor does your most important database server have?”, and I often get a “deer in headlights” look in response. Then a mumbled response, “I’m not sure, maybe a Xeon?”.

Read on for this rant, as well as the origin story of Glenn’s outstanding SQL Server Diagnostic Information Queries.

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The Joys of Replication, Example 48,106

Published 2022-07-14 by Kevin Feasel

Garry Bargsley troubleshoots a transactional replication issue:

Use transactional replication to replicate similar data from four databases to one Azure DB.  This sounds pretty straightforward for anyone who has done any replication work.

However, once I had everything setup and working, things stopped working, and it was a head-scratcher as to why.  I made the proper settings configurations on each article, or so I thought.  Let me show you the scenario in more detail.

Read on for the answer.

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Power Query’s Equivalent of IN

Published 2022-07-14 by Kevin Feasel

Gilbert Quevauvilliers is making a list:

In the example I did not want to specify all the country names one row at a time. This not only takes a long time, but if I had to then make updates it could be painful too.

The requirement was for certain countries to have their names and the rest be grouped into “Other Countries”

Read on to see how Gilbert was able to combine the set of “Other Countries” together.

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Indexes: Gotta Add ‘Em All

Published 2022-07-14 by Kevin Feasel

Andy Yun tells a tale of woe:

I once worked for an Entity Framework SaaS company that was having horrific T-SQL performance issues. We put out a major release one weekend and spent the subsequent week buried in horrible performance hell. Because all T-SQL code was generated from Entity Framework (stored procedures were banned by a development exec prior to me joining the company), there were no easy fixes that could be implemented (and a Production release typically took 12 – 36 hours, I wish I was joking).

The manager of infrastructure had heard about SQL Server’s missing index recommendations:

Yep, it ends about as poorly as you’d expect.

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