Wednesday 2:00 PM - 3:10 PM · Room 343

Now Where Did THAT Estimate Come From?

Hugo Kornelis

I make SQL Server fast (.com)

The SQL Server Query Optimizer makes its plan choices based on estimated rowcounts. If those estimates are wrong, the optimizer will very likely produce a poor plan. And there's nothing you can do about it. Or is there? In this session, you will learn exactly where these estimates come from. You will gain intimate knowledge of how statistics are built and maintained and how they are used to estimate row counts. But you will also learn how filters and joins influence those estimates. Though the focus of this session is on understanding the cause of bad estimates, you will also learn ways to fix the problems and get better estimates - and hence, better performing queries.

Wednesday 2:00 PM - 3:10 PM · Room 347

Learn how to troubleshoot SQL Server like a Microsoft engineer would

Arvind Shyamsundar

Principal Product Manager, Microsoft

How many times have you wished that you could self-diagnose a really strange issue with your SQL Server, that did not seem to be related to typical reasons like missing indexes, query plans, lock blocking, etc.?

• Maybe you are seeing unexplained high CPU usage.
• Maybe you have blocking, but it's on a really strange wait type that you've never seen before and does not show up in your web searches.
• Maybe you are seeing unusually high memory consumption in a memory clerk that you have never heard of?

You get the idea - all of us have had these head-scratching moments. Having the right tools and techniques at your disposal is crucial for diagnosing and resolving these issues efficiently and on time. Join us for an in-depth exploration of SQL Server extended events, wait statistics, call stack information, and debugging symbols. We will demonstrate how to leverage these powerful tools to gain a comprehensive understanding of the root causes behind various issues like the ones described above.

This will not be an introductory or general troubleshooting session. It assumes that you are familiar with the usual tools of the trade and want to know more. In other words, you are asking yourself - "can I do what the Microsoft support engineer would do"?

Through real-world scenarios and hands-on demonstrations, you will learn how to apply these tools effectively to diagnose and resolve SQL Server performance issues. By the end of this session, you will be equipped with a robust toolkit which will help you get a deeper understanding of SQL Server internals. And who knows, you might just be able to skip that support call to Microsoft and be the hero who saved the day!

Friday 9:00 AM - 10:10 AM · Room 343

Approximate functions: How do they work?

Hugo Kornelis

I make SQL Server fast (.com)

Sometimes, a close approximation is good enough. And sometimes, a close approximation is a lot faster. Microsoft has introduced “Approximate Query Processing” (the APPROX_COUNT_DISTINCT and APPROX_PERCENTILE functions) to give you exactly that benefit when you don't need exact answers.

But do you have a good response when you propose to use this function and your manager asks you to explain how they work first? Or is your only option to claim "black magic by smart Microsoft engineers"?

The algorithms used are not a secret. HyperLogLog and KLL Sketch. And now you most likely know exactly as much as you already knew before. And when you google for those terms ... you end up with a headache.

Time to join me for a session where I explain the black magic in the simplest possible terms, so that you can then explain it to your manager!

Friday 9:00 AM - 10:10 AM · Room 348

Mastering Elastic Database Pools: Best Practices and Troubleshooting from Microsoft Support

Jose Manuel Jurado Diaz

Microsoft, Escalation Engineer, Azure SQL Database and Manage Instance

Juan Moreno Romo

Microsoft, Support Escalation Engineer, Azure SQL Server Hybrid

Join us for an in-depth exploration of Elastic Database Pools, the game-changing technology that empowers developers and DBAs to efficiently manage and scale their databases. In this session, we'll delve into best practices and strategies for leveraging Elastic Database Pools to optimize your workload management and improve performance. Drawing from real-world support cases at Microsoft, we'll demonstrate the significant impact and benefits of using Elastic Database Pools in various scenarios. Our talk will also cover essential troubleshooting techniques to identify and resolve incidents effectively. Plus, don't miss our live demos showcasing practical examples and code in multiple programming languages. Whether you're a seasoned developer or a DBA looking to enhance your toolkit, this session is tailored for you! Gain valuable insights, practical tips.