SQL Index Creation Using DROP EXISTING= ON

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When you are making changes to an existing Non-Clustered index SQL Server provides a wide variety of options. One of the more frequently used methods is DROP EXISTING; in this post you will learn all about that option. This option automatically drops an existing index after recreating it, without the index being explicitly dropped. Let us take a moment understand the behavior of this choice. DROP EXSITING=ON which is my preferred method, will DROP the current index only after it finishes creating and building the index with the new definition. The pitfall is that if the index does not exist, you… Continue Reading

Identifying SQL Server Performance Problems Part 2

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Performance Monitoring Tools In this second post we are diving into what tools you can use to capture the important performance metrics you need to gather for baselining your environment. Be sure to read part one first. Performance Monitor First let’s start with what comes native to Windows Server platform, whether you are on an Azure SQL Virtual Machine or your standard SQL Server instance install on premises you have a native tool, called Performance Monitor (affectionately known to most as PerfMon). This reliable tool allows you to easily monitor performance metrics through a Graphical User Interface (GUI), by selecting performance counters for the operating system… Continue Reading

Mastering TempDB: The Basics

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I regularly deliver a presentation called “Mastering TempDB”. I wrote it based on what I wish I knew about TempDB “growing up” in my career as a SQL Server DBA. It really is a breakdown of what TempDB is, how it is used, what problems actually occur within it, and how to best configure it. With advice from my colleagues, I have decided to break that down into this article to educate you. What is TempDB? TempDB is a global resource used by everyone and everything inside SQL Server. Think of it as a dumping ground for anything that doesn’t… Continue Reading

Identifying SQL Server Performance Problems Part 1

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Every server, database, storage appliance and network encounter some sort of performance issues. It is a major part of our job as database administrators to properly monitor and fix those performance issues whether it is in your traditional on premises environment or in the cloud. This article will cover ways monitoring performance and how to establish a baseline. We will go over several important performance metrics every database administrator should know and how to gather and interpret those metrics through several different options within SQL Server and your Windows operating system. Now which tool you use to accumulate these metrics… Continue Reading

Storage Tiers What SQL Server DBAs Need to Know

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“One Gerbil, Two Gerbils or Three Gerbils?” is a common DBA joke about server and storage performance. No matter how many gerbils power your storage, you need to know what type they are and the power that they provide. Storage is not about gerbils it is about IOPs, bandwidth, latency, and tiers. As a DBA it is important for you to understand and know what kind of storage is attached to your servers and how it is handling your data. It is not important to master everything about it, but it is very advantageous to be able to talk to… Continue Reading

Resizing Tempdb (When TEMPDB Wont Shrink)

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Occasionally, we must resize or realign our Tempdb log file (.ldf) or data files (.mdf or .ndf) due to a growth event that forces the file size out of whack. To resize we have three options, restart the SQL Server Service, add additional files, or shrink the current file. We most likely have all been faced with run away log files and in an emergency situation restarting the SQL Services may not be an option but we still need to get our log file size smaller before we run out of disk space for example. The process of shrinking down… Continue Reading

Adaptive Joins in SQL Server

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SQL Server 2017 (compatibility 140) brought us many Intelligent Query Processing (IQP), formally known as Adaptive Query Processing, features that improve performance on workloads straight out of the box with no code changes to implement. One of those features introduced was Adaptive Joins. In this feature the join operator is dynamically determined at runtime by the optimizer, which defines a threshold number of rows and then chooses between a Nested Loop or Hash Match join operator. This operator switch can produce a better join and improve performance of your queries without you having to lift a finger. Not all queries… Continue Reading

Change Azure SQL Database Service Level Objectives in SSMS

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Sometimes as a DBA, I am lazy and want the ability to execute all of my tasks in one place. Lucky for me I discovered the other day that I can change my Azure SQL Database Service Level Object options within SQL Server Management Studio (SSMS) without ever having to go to the Azure Portal. By right clicking on your database properties and choosing the Configure SQL page you can change your Subscription and Azure Location. Even more and what is really cool is I can also scale up and down my Edition (which is generally referred to as Service… Continue Reading

Caution When Dropping Unused Indexes on an Azure SQL Database

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Index Maintenance is an important aspect of database health. Above and beyond regular index rebuilds and reorganizations it is important to understand the usage of the indexes on your database. Cleaning up unused indexes can save a lot of overhead on Insert/Update/Delete operations. To achieve that goal, I typically run a script like the one shown below and check out whether or not an index has had any seeks or scans against it as a starting point in my cleanup regiment. SELECT d.name,        OBJECT_NAME(i.[object_id]) AS [ObjectName],        i.[name] AS [IndexName],        s.user_seeks,        s.user_scans FROM sys.indexes AS i    … Continue Reading

What is Azure SQL Database Serverless?

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What is Azure SQL Database Serverless? When I hear the term serverless my mind gets confused. How can a database exist without a server? Azure is a cloud platform, is my database just floating in the air? No, I am not really thinking that, but still the word serverless can be hard to understand. So, let’s walk through what it is. Serverless is a term commonly used for function as a service patterns like Amazon Lambda, or Azure Functions, where you have a piece of code that is called and executed without you deploying any infrastructure. Azure Logic Apps are… Continue Reading