Bob Pusateri (B|T) tweeted a quote image that really struck a chord with me and elicited a strong reaction from myself. It got me thinking I need to write a blog on this, so here we go. Many times, over the years I’ve had conversations with people in which they have said things like below. “I can’t learn anything new because my work won’t send me to training” “I can’t learn about xyz because my boss or coworkers won’t sit down with me to show me how” “I don’t have time to learn anything new” “We’ll never go to the cloud, so I don’t need to know that” “I’m too busy…
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Query hints are always about tradeoffs—typically you are giving up something, such as flexibility, to achieve more consistency, or very specific performance characteristic. One example of this migt when returning code results, that you would want to see the data as soon as possible, even before the complete set of data has been returned. Did you know that you can return a subset of rows to look at BEFORE the entire result set is returned? The FAST n query hint allows the optimizer to return a specified number of rows as quickly as possible. Imagine an application result screen where users frequently wait for data to appear. Wouldn’t it make…
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Speaking Engagements Check out my new Event Calendar, to see my upcoming and past speaking engagements. You can catch me at various events throughout the year. If you are interested in having me speak at your event reach out via my contact me page.
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I’ve written about statistics in SQL Server a few times now. Through conversations I am reminded that not everyone keeps their table statistics up to date. Keeping your statistics up to date is one of the more critical components of SQL Server performance issues. Please be sure you are doing more than just index maintenance to maintain your statistics. Index maintenance only maintains statistics created by indexes and single field predicate created table statistics. There are also column statistics that need to be maintained that are created by predicates usage in your queries or even manually created. For each insert, update, or delete the distribution of your data changes and…
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It is widely known that I am a horrible speller and hate to type code. I tend to use a lot of code snippets and reuse code to avoid writing it. So, when I find little tips that make coding easier for me, I like to share. Did you know that you can surround your code with a click of a button with IF, BEGIN END, WHILE code blocks? SQL Server Management Studio (SSMS) gives us the basic structure of a Transact-SQL statement code block as a starting point. Take Look In SSMS In a query window, Right Click and Choose Surround With (note the hot keys of Ctrl+K or…
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Several times I’ve been asked what tools are in my performance tuning and SQL Server management arsenal, so I decided to just create this blog to list them out for you. Keep in mind, these are ones I personally use. There are many more out there that the community uses. Feel free to comment with any you may use that is not on my list. Community Tools (Free) Ola Hallengren’s Maintenance Scripts- Index Maintenance, Integrity and Backup Scripts https://ola.hallengren.com/sql-server-index-and-statistics-maintenance.html Glenn Berry’s Diagnostic Scripts -Various scripts based on DMVs to extract SQL Performance statistics and information https://www.sqlskills.com/blogs/glenn/category/dmv-queries/ Adam Machanic sp_WhoIsActive See what is currently going on in SQL…
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Indexes can be incredibly beneficial to your database performance; however, they do come with a cost—indexes both consume storage space and affect insert performance. Therefore, it is important as part of your index maintenance procedures that you periodically check to see if your indexes are being used. Many times, indexes are created in the belief they are needed but in fact they are never used. You can reduce that IO overhead on inserts when you remove unnecessary indexes. How Do You Find Them? Glenn Berry (B|T) has a fantastic script as part of his diagnostic scripts (link) that helps identify index utilization. In his diagnostic scripts it is listed as…
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Some of us take days and weeks to write a blog, while others can take two minutes and write a great blog *cough* *cough* Denny (B|T). Why is that? I think it’s simple, we are thinking to hard about it and over complicating things. Just sit down at your computer and write what’s on your mind. It doesn’t have to be rocket science or something completely mind blowing or life changing. I’ve seen several, as of late, crowd source their next topic, I think this a great avenue to take as it is those people that are likely your readers. There’s nothing wrong with asking others what you should write…
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My last two blogs were on understanding columnstore and creating columnstore indexes. In this post, I will touch on one last topic, when to use columnstore indexes. As noted in my prior posts these indexes are designed for large data warehouse workloads, not normal OLTP workload tables. As with any index design it is important to know your data and what you will be using the data for. Be sure to look to what types of queries you will be running against it, as well as how the data is loaded and maintained. Let’s look at a few questions you should ask yourself before deciding to implement a columnstore index.…
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In my last blog I explained what a columnstore index is, in this blog, we will dive into creating a clustered columnstore index and look at the performance differences the index can make. Let’s get started. Using AdventureworksDW2016CTP3 we will work with the FactResellerSalesXL table which has 11.6 million rows in it. The simple query we will use as a demo just selects the ProductKey and returns some aggregations grouping them by the different product keys. First, we will run the query with no existing columnstore index and only using the current clustered rowstore (normal) index. Note that I turned on SET STATISTICS IO and TIME on. These two SET…
