Voice of the DBA

Category: Editorial

  • Mission Critical Deployments

    Talk about a lot of pressure to get a software deployment correct. A software install on an Airbus airplane resulted in a file containing parameters being wiped. This error caused (apparently) an airplane to crash when three engines cut off in flight and four people were killed.

    I don’t know if this is the final report on this, but the fact this is a possibility concerns me as a technologist. Certainly we have probably had similar mechanical failures and installation issues in the past, but there are some scary issues here with regards to software. There was a faulty software installation (yikes!), a poor architecture (not assuming more then 2 engines would stop), too much tolerance for software errors (the review letting this pass), and poor overall design (no alerts on the ground).

    I can’t decide if I think that software makes issues like this more or less likely. Certainly checks of physical systems are skipped regularly by people. It’s far easier, and more reliable, to automate checks of software systems, especially with deployments, than it might be for complex mechanical changes. However, maybe that’s not true. Perhaps mechanics are more likely to notice a loose bolt than a misconfigured software menu. Or maybe we need a new type of mechanic that’s savvy with technology.

    Ultimately I think that any software that makes changes to systems, including through deployments, needs to have double checks by an independent process and clear alerting of any issue, not relying on someone to look for the success of a long series of steps. We also need to take review of potential software errors very seriously and ensure the tolerance for potential issues shrinks as the impact of those issues rises.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.2MB) podcast or subscribe to the feed at iTunes and LibSyn. feed

  • How many environments?

    One of the things I’ve learned over time is that in order to develop software, you need multiple environments. I think that outside of school projects, I’ve always used at least two environments: development and production. At school there were times I worked on software that I also used, and would make changes on my live (and only) system. I had no shortage of regrets, and whenever I question using a Version Control System (VCS) or separate environments, I think back to those days.

    People I meet these days that develop software almost always have more than one environment, and most have at least 3. The most common model might be development, test, and production, but plenty of people work with even more. Maybe not as many as the seven Grant once had to deal with, but I have worked in environments where we had six database environments for one of our software pipelines.

    How many different environments do you work with?

    The poll this week asks for the count in your organization. I realize that you probably have multiple applications and test environments, but choose one or more and give us some answers.

    The most I’ve worked with was in a financial services company. We had a development database and a separate QA system for testing. There was a staging system to mimic production, a Beta database for users to actually test against and production. That worked well, and we were able to easily refresh environments as needed without impacting our development efforts. Mostly because we have a strong DevOps type process.

    Let us know this week how you’ve got your systems set up and what each one is used for in your software pipeline.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.8MB) podcast or subscribe to the feed at iTunes and LibSyn.

  • The Tally Table

    I saw a someone post a question recently about solving a T-SQL problem. One of the answers given used a tally table, which the original poster didn’t understand. A few follow up links pointed them in the right direction, but it got me wondering.

    How many of you know what a tally table is and how to create one? I bet a few of you don’t, which might mean you’ve never had the need. Or it might be a hole in your skill set and you didn’t realize that a tally table can be very useful in solving a number of problems. Anything from generating dates to splitting strings. There are plenty more ways to use one, and feel free to mention more in the comments that others might not have tried.

    I’m not sure the tally table is a core T-SQL skill, but I think it’s an important one you should learn as you grow your skills. After you’ve mastered the basics (Insert/update/delete, aggregates, outer joins) Adding in an understanding of window functions, the APPLY operator, and CTEs are also important to allow you to become better at solving the problems you run into with more efficient T-SQL.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 1.7MB) podcast or subscribe to the feed at iTunes and LibSyn. feed

  • Business Pressures

    I know a little something about building and scaling a system on the Internet. While SQLServerCentral isn’t the largest site out there, we’ve had lots of experience with growing a site while trying to manage a business. We were successful at it for years before Redgate Software purchased the site. I’d like to think we’ve continued to run the site successfully and balance the commercial needs with our goal of hosting a world class SQL Server community that educates the community on a daily basis.

    I thought back about our history and the way things have gone while reading an article on Github and some of the challenges they have faced they they try to build a business from their (primarily) free service. I certainly hope they succeed as I really like the Github model and only hope their investors are as enlightened and visionary as the founders of Redgate.

    There are constant challenges in running a business. No matter how good your intentions, the pressure to break even or turn enough of a profit to survive are always there. At the same time, there is just as much pressure from ethical business owners to keep their customers’ and clients’ expectations and needs in the forefront of their minds as they run their business.

    I have struggled with this regularly at SQLServerCentral and still do today. Serving the community while providing value for my boss (or making a profit to pay my salary in the past) are two conflicting goals. I think that things have worked out well, but I am constantly striving to maintain some balance between what is best for all.

    I do hope GitHub and many of the low cost services are able to transition and survive as they mature as businesses. Even if many of them can’t continue to provide the same services for free, I hope customers see enough value to pay for some level of service, and the sites survive.

    Steve Jones

     

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.4MB) podcast or subscribe to the feed at iTunes and LibSyn.