27Jan 2016 by Grant Fritchey 4 Comments

The Importance of a Full Backup in SQL Server

Database Lifecycle Management, DevOps, Professional Development, SQL Server, SQL Server 2016
This is the first of 12 posts this year in support of Tim Ford's #iwanttohelp initiative. These will be completely 100 level, introductory blog posts meant to help people that are just getting started as data professionals. I'll try to cover several different topics over the year, but felt I should start with what I think is the most important, backups. It is impossible to overstate the importance of getting a good backup of your SQL Server databases. A backup is the most fundamental of protections for the information on which your business is dependent. Since SQL Server is a service, it manages it's own files. Because of this, you can't just copy the *.mdb file where your data is stored. Instead, you must run a process, usually through the…
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20Oct 2015 by Grant Fritchey No Comments

Statistics for the New Data Pro

PASS, SQL Server, SQL Server 2016, T-SQL
Next week at the PASS Summit I'll be presenting a session called Statistics for the New Data Pro. You can read the abstract at the link. I just want to emphasize that this is a beginner level session. I think way too many people who are just starting out with SQL Server don't understand the role that statistics play in determining how your queries are going to behave. What's more, too many people don't know how to get and read statistics to understand how it is that the optimizer thinks you have X number of rows in your database that match a given value. I'm going to make darned sure that the people who attend this session come out with a full understanding of how to read the statistics. This includes…
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09Sep 2015 by Grant Fritchey 16 Comments

Yes, Foreign Keys Help Performance

SQL Server
I created this example several years ago that illustrates how foreign key constraints can help performance. It's a contrived example. Granted. I feel like it illustrates the point. However, over the years, people have questioned one aspect of it. The optimizer uses the foreign keys to figure out which tables can be eliminated from the query, making for a more efficient plan and making the query run faster. The pushback has always been, "Yeah, Grant, but nobody writes T-SQL where they include extra tables that they don't need." My initial response, after I stop laughing, is to point out any number of ORM tools. But, you know what, let's assume that's correct. No one would ever create a giant catch-all view that has all their JOINs in one place so they don't have…
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10Aug 2015 by Grant Fritchey 3 Comments

Generating Estimated Plan and the Plan Cache

SQL Server, T-SQL
Does generating an Estimated Plan cause that plan to be loaded into the plan cache? No.   What? Still here? You want more? Proof? Fine. Let's first run this bit of code (but please, not on your production server): DBCC FREEPROCCACHE(); That will remove all plans from cache. Now, let's take this query and generate an Estimated Plan (CTL-L from your keyboard or by clicking on the "Display Estimated Execution Plan" button on the toolbar): SELECT * FROM Production.ProductModel AS pm; This will generate a trivial plan showing a scan against the Production.ProductModel table. Now, let's run another query: SELECT deqs.plan_handle FROM sys.dm_exec_query_stats AS deqs CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest WHERE dest.text = 'SELECT * FROM Production.ProductModel AS pm;'; That's just an easy way to see if a plan_handle exists.…
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06Aug 2015 by Grant Fritchey 1 Comment

Reading Your Execution Plans

SQL Server
I'm putting the finishing touches on the all day seminar on execution plans that I'll be putting on at DevConnections this year. I have tons of examples to show you how to interpret execution plans as part of query performance tuning. We'll be able to fill our time. However, I've got a pretty high degree of flexibility on which examples I use. With that in mind, I'd love it if you could bring in your own execution plans that you'd like some help reading. I won't guarantee a solution for your query problems, but I promise to read through it and make some suggestions. If you have an execution plan that you don't mind sharing with the group and you'd like a little consulting time on tuning the query, bring it…
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03Aug 2015 by Grant Fritchey 6 Comments

Differences Between Actual & Estimated Plans

SQL Server, T-SQL
I have, in the past, made way too much of the need for Actual Plans when doing performance troubleshooting. The primary reason for this is to get the Actual Plan in order to see the differences between the Actual and Estimated Row Counts as a means of understanding how the optimizer saw the data. But, is that the only thing that's different between Actual & Estimated Plans? Well, pretty much, yeah. I took two fairly average execution plans from SQL Server 2014 and ran them through Altova's XML Spy, which does XML comparisons similar to how Redgate SQL Compare will compare two data structures for you. Here is every single difference I found. Everything was additional information in the Actual Plan. In the information for the first operator, in my case,…
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29Jul 2015 by Grant Fritchey 1 Comment

Hey Kids! Let’s Put on a Show at the Old Barn

Azure, Database Lifecycle Management, DevOps, PASS, SQL Server, T-SQL
Alternate Title: I'm traveling a bunch. Let's get together and talk. A bunch of trips and presentations coming up, so I thought I'd share. First, I'll be SQL Saturday Omaha for my first time ever presenting in Nebraska. I'm excited to add this state to my list (which is almost over 40 now). If you're not doing anything August 15th, let's have a chat. Next, fingers crossed, I'll get selected to fly back to my home state, Oklahoma, to go to SQL Saturday OKC. These guys put on a great event and hey, it's Oklahoma so how can it be bad. I hope they announce soon. I need to schedule my flights. This one is on August 29th. September also has several events. First, I'll be at SQL Saturday Las…
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20Jul 2015 by Grant Fritchey 5 Comments

SQL Server Management Studio – Footloose and Fancy Free

Azure, SQL Server
That's right. There's been a divorce. SQL Server Management Studio (SSMS) has been divorced from the server product. In fact, Microsoft is inviting you to the new SSMS coming out party. I'm pretty excited about this. While I'm very comfortable in SSMS, to a large degree, it's like that old pair of jeans that you've worn for the last 10 years. They're comfortable too. Well, maybe a little tight when you pull them on out of the wash. One of the knees is gone. The legs are frayed so much it almost looks intentional. You just noticed a hole in the bottom. The zipper is acting up... Yeah, OK. These jeans have had it. So has SSMS. The plan from Microsoft is to upgrade SSMS independently from the boxed product. In fact, since one of…
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06Jul 2015 by Grant Fritchey 4 Comments

But I Don’t Have a Test Server…

Database Lifecycle Management, DevOps, SQL Server, T-SQL
I frequently see statements on forums along the lines of "I don't have a test server, so I'm going to do something I've never done before directly on my production servers..." This is usually followed by questions along the lines of: But that's OK and I won't get fired, right? So how do I know if it worked? Is that dangerous? The replies are: No. You should be fired You won't By All the Gods! Yes! It's stupidly, insanely, I don't really like my production server, my data, my boss, or my job, dangerous. Yes. I understand. You're working for a not-for-profit, so you can't afford tons of new servers. You're looking at a 50tb production server of which, you can't make a copy. Your bosses just don't want to spend the…
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26May 2015 by Grant Fritchey 11 Comments

Database Engine Tuning Advisor

Azure, SQL Server, T-SQL
I would love to see the Database Engine Tuning Advisor (DTA) pulled from the product. Completely. Heck, I feel bad that I included a chapter on it in my query tuning book (all updated for SQL Server 2014 by the way). Let me tell you why we need to pull this tool. First, I understand its purpose. It's supposed to be a fast and easy way to get some performance tuning done for people who just don't have the time or knowledge to go through the full process of gathering metrics, evaluating poor performers, understanding root causes and applying indexes to fix those causes. I also readily acknowledge that it actually is an amazing piece of software. If you don't agree with that, go read this white paper. With those acknowledgements…
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