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 that file can get tricky so I created this flow…
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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 will qualify for this new feature. The feature only applies…
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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 Tier outside of SSMS), Size and Storage Tiers as well.…
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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 LEFT OUTER JOIN sys.dm_db_index_usage_stats AS s ON i.[object_id] =…
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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 another version of this—a program that exists to do a…
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As you know, I spoke to 12 Chapter Leaders and 4 Regional Mentors yesterday. All are very upset with PASS right now and feel slighted, which as a volunteer myself, I empathize. I have given the feedback, to you. After talking with them here is where the problem lies IMHO: communication and transparency. We received an email taking away our token of appreciation PASS gives us for all our yearlong hard work that helps to build and amplify this community. In the email we also were asked to please promote and encourage Summit registrations among other things. You cannot take something away and then turn around and ask the leaders…
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Under compatibility level 150, in both SQL Server 2019 and Azure SQL Database, you now can use batch mode for CPU-bound analytic type workloads without requiring columnstore indexes. There is no action needed to turn on batch mode aside from being on the proper compatibility mode. You also have the ability to enable it as a database scoped configuration option (as shown below), and you can hint individual queries to either use or not use batch mode (also shown below). If you recall in my earlier blogs on columnstore, it is batch mode in conjunction with page compression that drastically increases query performance. This feature, Batch Mode on Rowstore, allows…
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On June 3rd PASS announced their annual Summit for Data Professionals was moved to a virtual format. This is not surprising to those of us in the SQL Server community. Many events are moving to a virtual platform as well as being able to offer them at no costs to all attendees. PASS though, is a different kind of “company” for lack of a better word. We are a community of people that built this “company” from the ground up. Due to normal day to day commitments, like jobs, most of us do not have time to run the day to day operations of the “company” and we rely on…
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The need to transition to virtual speaking engagements is not easy for me. As someone who loves public speaking and delivering in person training, not being able to do so right now is very difficult. I struggle with staring at my screen talking to my camera as a teaching mechanism. I get asked all the time to speak at virtual user group meeting and online conferences but usually kindly decline. Now that virtual events are our only avenue to speak, I am forcing myself out of my comfort zone and trying a few on for size. There are a several reasons why this is not my first choice in delivering…
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Knowing your data is very important when it comes to writing code. Now I’ll admit that I am very far from being a developer, however as a DBA, I spend much of my day’s performance tuning code. In doing so, I get to see many ways code can introduce excess database reads. One of the most recent things I have come across has to do with NULLs. The environment I was working in had no default values in their table design, so it was riddled with NULL values. Over the years they had implemented coding standards to try and mitigate these NULL values within their code. In every column search…
