In SQL Server the query optimizer uses a cardinality estimator to answer data SELECTIVITY questions like the ones below. The optimizer uses this cardinality data, which relies heavy on statistics to get the answers and calculate a cost estimate. It takes the #of Rows to Satisfy a Predicate/Total # of Input Rows. How many rows will satisfy a single filter predicate? Multiple? WHERE How many rows will satisfy a join predicate between two tables? JOIN How many distinct values do we expect from a specific column? DISTINCT GROUP BY From this estimate the optimizer is able to find an efficient execution plan that fulfills a query request. You will note that…
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Ever look back at old work and wonder what was I thinking when I did that? Or even better you mock and get disgusted over some code you stumble upon and then realize you wrote it? Today is one of those days. Lucky for me one of my clients is a company I used to work for. It’s awesome to be able to go back and work in an environment you are familiar with. However, with that, you realize when you worked there you made some decisions or wrote some code that you now shake your head at. On the other hand, it’s a really great way to see how…
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In my sessions, I always talk about how to build your skill set when you don’t have a budget for training. Well next week April 25-26 is one of those free opportunities I take advantage of each year. 24 hours of PASS, affectionately referred to as 24HOP, is an online training event comprised of 24 sessions in a day free training. Register here http://www.pass.org/24hours/2018/april/About.aspx One technical session is given every hour around the clock, so no matter what time zone you are in you can easily catch a session or two. It makes it easy to stream during work, during lunch or even just sit and watch it streamed to…
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Sometimes as a newbie to SQL Server using SQL Server Management Studio (SSMS) you don’t know about the little gold mines that are within the product that help you be a better DBA or Developer. Template Explorer is one of those. To get to it go to VIEW from the taskbar then Template Explorer. Alternatively, you can reach it with keyboard shortcut Control+Alt+T. When you click on it, another side window will appear showing you a list of all templates available within Management Studio. A basic example would be creating a new stored procedure, this template provides an easy starting point. Microsoft has even gone so far as to incorporate…
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When applying a new SQL Server cumulative update, hot fix, or upgrade SQL Server doesn’t always apply all the fixes in the patch. When you upgrade the database engine in-place, databases you had already stay at their pre-upgrade compatibility level, which means they run under the older set of optimizer rules. Additionally, many optimizer fixes are not turned on. The reason for this is that while they may improve overall query performance, they may have negative impact to some queries. Microsoft actively avoids making breaking changes to its software. To avoid any negative performance impacts, Microsoft has hidden optimizer fixes behind a trace flag, giving admins the option to enable…
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One of my goals for 2018 is to expand the reach of my blog. As a blogger starting out I had my own site I posted to, but my blogs only reached those who followed me on Twitter, Facebook, Google + and LinkedIn. My blog automatically posts to these three sites using a WordPress Jetpack Plugin called Publicize. After a few months, I discovered that syndication could be setup on other sites such as SQL Server Central. This allowed more people the opportunity to read my writing and expand my reach. Many sites, such as these will even send your blog out in newsletters like Database Weekly. Starting last week,…
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I am so thrilled to have the opportunity to expand my writing with my first Simple-Talk article posted. Simple- Talk is technical journal and community hub from Redgate. It in I discuss my passion for my work as a Lone DBA. You can find the full article using the link below. https://www.red-gate.com/simple-talk/opinion/career/survive-lone-dba/
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Here is a quick blog to show you something I discovered that I didn’t know existed. I was on a Skype call and noted that the presentation I had been watching was no longer audible. I tried messing with my volume, I made sure my sounds weren’t muted and played around with my speakers and still nothing. I could hear the skype call without issues, but I wanted to multitask and continue to listen to the presentation. Finally, a light bulb went off and I thought maybe windows was “doing me a favor” and turning off all noises why I am on Skype. Sure, enough it was. If you look…
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Last week, I got the chance to give my I’m It Survival Tips for the Lone DBA in a webcast for the first time thanks to the PASS Women in Technology Virtual Chapter. This is by far my favorite session to give because it’s real life and can pertain to all us. Whether you are a Lone DBA or part of a team, we all encounter the struggles when handling a heavy work load. I always love the interactions I get from this session. It allows us to share our stories and learn from each other. As a Lone DBA you are on call 24/7. You are required to stop everything and fix things…
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A few weeks ago, I wrote Part 1 and 2 of this series, which was a beginner’s guide to Always Encrypted. In part 3, I am going to go over what road blocks I ran into when trying to implement this solution for a client. The goal of the project was to prevent the DBA from being able to view salary information, while still allowing the application to function without issue. We were able to encrypt the data easily, but the entire process was not without issues. We had to remove default constraint values to get it to implemented. Always Encrypted does not currently support constraints. Fortunately, the defaulted zero…
