Voice of the DBA

Author: way0utwest

Interviews: What is ACID?

I once had a job interview with a large group of employees at a company. They were arranged around a table, with me at one end. The interview was a round robin affair, with someone asking me a question and me answering. They would take turns, going around the table for a couple hours. Not the easiest or hardest interview I’ve had, but one of the more interesting.

The first question from the gentleman to my left was, “What does ACID mean?”. My answer: “Isolated, Consistent, …”

I don’t have a problem taking a few seconds to think, but I have that internal clock, much like an American football NFL quarterback. Mine is not the 5 second one many QBs have, but I know that after about 20 seconds, people are wondering if I’ll answer at all. Or if I’m still focused on the interview. If I go 30 seconds, I might have blown the interview. What would you do here? Do you know the other terms? More importantly, can you answer at a level beyond the words of the acronym?

My response after 10 seconds or so was to admit I couldn’t remember the word. I could google for the meaning, but I did know this applies to relational database transactions, intending to ensure that we always have a known state for our data. We know that each transaction must full complete or be completely undone. We can’t have the classic issue of depositing money in one account and failing to remove it from another. We also cannot have other transactions interfere with other’s work. This means a transaction on a piece of data must complete before the next transaction can modify it. We also must ensure that if the system were to crash, our database could not restart with data in an unknown state. Therefore, in SQL Server, we write to the log first, ensuring the transaction is complete before we can be sure the data changes are hardened. There are more details you could add to my answer, but this is a core foundational part of relational databases.

I have never been asked this question in another interview, but I do think this is one of those core concepts that helps me understand and explain other parts of SQL Server, and even of how to build software. I think understanding this will help you answer other interview questions with more depth and knowledge. Hopefully, you’ll have a better answer than I did, with the actual words that make up the acronym.

Steve Jones

The Voice of the DBA Podcast

Listen to the MP3 Audio ( 3.8MB) podcast or subscribe to the feed at iTunes and Libsyn.

September 20, 2017
The Library Job Hunt

I was reminded of the ways I’ve looked for jobs by a post from the Job Headhunter about library time. Rather than looking for what jobs are available, the recommendation is to take a targeted approach of using the library as a place to focus your energies and find the job that you really want, or at least type of job you want.

Far too many of us look for jobs when we need them, often feeling financial pressures to accept the first offer we get. The pace of hiring usually prevents us from considering multiple offers, as the timing of interviews may not align. We make decisions for expediency, more than any other reason.

We also usually fall from job to job, perhaps accepting a position that doesn’t quite suit us, or keeps us in the same position when we’d rather move. Again, time and financial pressures can force bad decisions. There’s also the fact that despite the training and schooling many of us have gone through, we don’t usually think about other options in the hectic, day-to-day chaos of our lives.

The Job Headhunter recommends spending time in the library researching and thinking about different jobs. Certainly you could do this from the comfort of your home with technology, but I agree with the premise. The library can help you focus without the distractions at home. You can spend time thinking about your life, your goals, your interests, your skills, and more. Come up with a plan that drives your career forward. Certainly your research might give you some unexpected answer, but likely this will help you focus on some intersection of your skills and interests.

Life is short, and there are opportunities out there for you. Choose the ones you want, hone your skills, and actively pursue the employment that fits in your life. The work, the company, the location, whatever is most important to you.

Steve Jones

The Voice of the DBA Podcast

Listen to the MP3 Audio ( 3.0MB) podcast or subscribe to the feed at iTunes and Libsyn.

September 19, 2017
Join me at VS Live – Anaheim

We’re just a month away from Visual Studio Live in Anaheim where I’ll be speaking along with many others. Join me today, register with ANSPK14 and save $400. This gives you the 4-day, all access conference package for a reduced rate.

California coding, with experts in DevOps, Cloud Computing, Databases, Visual Studio, Mobile, and more. This is a multi-technology conference, and you can learn about all those different technologies where you need to work.

The Agenda is packed, and I’ll be covering security and testing for SQL Server, but I’m looking forward to checking out some Azure, VS and VSTS tricks, Lambdas and more.

If you’re looking to learn some SQL Server and more this fall, think about joining me in California for a warm break. Register today and enjoy some fall learning in LA.

September 19, 2017
Experimenting with VSCode instead of the ISE

I’ve been playing with PowerShell here and there, learning a few things. As I use the dbatools project, or

I saw a tweet from Rob Sewell on using VS Code for PoSh, which I’ve tried, but it felt cumbersome and hard. I didn’t spend much time on it before dropping back to the ISE, which I was comfortable in.

However, Rob’s tweet mentioned a post from Mike Robbins on configuring VSCode, so I decided to give it another try. It’s not that the ISE doesn’t work well, but I keep hearing people talking about VSCode, which has git support, and so I thought this might be worth trying.

I won’t talk about anything in Mike’s post. You can try that out. I already at the PoSh extension, but it was upgraded since I first used it, and now pops the integrated console when I open a .ps1, which makes it like the ISE.

I don’t remember that from before, and I certainly like that. I also skipped the VSCode-icons in place of VSCode Great Icons. I mean, I want to be great at this stuff.

The one thing I did do was change the settings from Mike to set a new zoom level. Zero is a little low for my old eyes, and 2 (where I’ve been working) is too big here. I chose 1.

Using VSCode

The main thing you want to do with an editor is write code. So, I decided to write some simple code. I have a few things to do, but I decided to start with something simple. I wrote a few lines of PoSh. This isn’t terribly useful, but I wanted to play with the editor and the debugger.

Now, in the ISE, I do get some intellisense and parameters. The parameters look better, but the screen capture ghosted them out a bit.

In VSCode, this actually looks better. First, I enter a cmdlet name and see some basics.

After I’ve entered it, I see more details as I work with it.

Running code works OK. I can hit F5 and the code runs. Not ideal, as the function keys make my hands move off the keyboard. That isn’t different from the ISE. I definitely wish we had shortcuts, and I know there are extensions to help with this. I need to play with some.

The debugging, however, is much easier. More in line with VS and other debuggers. Set a breakpoint, F5, and I have real debugger controls if I want them (as well as F10, F11).

I can see variables in the debug window, or in the main window if I hover. This feels a bit cleaner than the ISE.

There still are some issues. F10 seems to disappear sometime. I’ve tried to remove breakpoints and they don’t always remove. However, those are pretty minor items in the scheme of things.

Overall, I’ve changed a bit of my view of VS Code here. It does seem to have improved since the last time I tried PoSh in here. Maybe I’ll give it another chance with other languages as well.

September 18, 2017