What’s in a Number?

In one of our matches last season, my girls scored 5 goals.

Now I’ll ask you a question. What’s wrong with that statistic?

It’s useless!

But why? When you look at the score of a soccer match, it’s pretty clear – you have nothing against which you can compare it. The obvious missing ingredient is the number of goals the other team scored. With that additional piece of data, so much more is gained. What if the other team scored 0? Or 4? Or how about 12? Each of those numbers, paired with our score, tells a story. But one score alone does not.

If this is so clear in sports, though, why do we repeatedly overlook it in the business world? I was on a discovery call today with a customer who shared a metric they track. It’s a raw number. Not a percentage or anything else that can be compared – just a raw number. And then the customer went on to dismiss the metric as being largely ignored. But it was clear from the call that he hadn’t given any thought to why it was ignored, only that it is.

In his defense – and this customer shall remain nameless, anyway – I think the raw number metric was someone else’s idea and he was only relaying information in this case. But I was still concerned by the fact that it wasn’t immediately apparent to him why it’s ignored.

By the way, what I’m sharing here is not original. My own attention was first drawn to it by Rob Collie (T|L). He presented a session at IndyPASS a couple of years ago on aspects of data, and included this wisdom. When analyzing data, look for key words in the name; words like “by”, “of”, “per”, and “versus”. “Actual Widgets Produced” is just a number. “Actual Widgets Sold VERSUS Forecasted Widgets Sold” is a valuable metric.

The Dow Jones closed at 29,395.33 on Friday. So?!?! That was down 0.12% from the close on Thursday. Ok, now we’re getting somewhere. Give me Friday’s raw number and it tells me nothing. Compare it to Thursday’s and now I have something to work with. I can surmise that Friday was kind of a “meh” day for the stock market. So if my own portfolio took a hard turn one way or another, it might be something worth checking into. But if all I had was Friday’s close, I wouldn’t know that.

Anyway, the reason I bring it up now is because it is so rarely recognized. And it’s the simplest of concepts that can turn useless data into actionable metrics. Whenever you are analyzing anything, ask yourself, “What am I comparing this against?” If the answer is “nothing” then you need to adjust your metric.

I hope this helps. Oh, and that other team scored 2 goals. So we won the Shelby County Derby this year. Go Tigers!

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VSCode Extensions in SQL Ops Studio

The list of extensions for SQL Ops Studio is still pretty small. But since it’s a fork of VSCode, it’s possible that any given VSCode extension just might work fine in Ops Studio. If that’s the case, here’s what you can do.

  1. Go to the VSCode Marketplace and find the extension you want. In my case, I’m adding the tsqllint extension that I mentioned in a previous post.
  2. Under the Resources heading on the extension’s Marketplace page, you’ll see a link to “Download Extension”. This is a .vsix file that you’ll want to save to your local system.
  3. In Ops Studio, under the File menu, click “Install Extension from VSIX Package”. Pick the file you downloaded. Once it’s installed, Ops Studio will prompt you to Reload for the new extension to take effect.

And that’s all there is to it! Once again, I’m indebted to ck (twitter|blog) for finding this.

If you try this with an extension and run into a problem, I’d like to hear what it was. I’m curious about which extensions don’t carry over well, and why they have a problem.

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T-SQL Tuesday #106

This is a response to T-SQL Tuesday #106, Trigger Headaches or Happiness, by Steve Jones.

I can only recall one time in the past several years (at least a decade) that I’ve found triggers to be useful. It involves data migration.

The problem: You have a massive, high-activity table. Let’s call this Table_A. You need to make significant changes to it. For example, the clustered index needs to change. How do you accomplish this?

The solution: Create a script that does the following:

  1. Create a second table, which we’ll call Table_B. This one will eventually become the new Table_A, so design it with your changes in mind.
  2. Create a third table, which we’ll call Table_C. This one is like Table_A as it is now, except that it includes an additional identity column, and is clustered on that column. Assuming there’s an existing clustered index on Table_A, recreate that as a non-clustered index on Table_C. Depending on how Table_A is updated, you may need additional columns to track what updates occur.
  3. Create a trigger on Table_A. This trigger duplicates all changes in Table_A to Table_C.
  4. Looping via a suitable batch size for your environment, write all rows from Table_A to Table_B.
  5. Looping again, write all rows from Table_C to Table_B (taking into account the appropriate insert/update/delete logic for your situation). Note where you stopped with Table_C, the “high water mark” for that identity column.
  6. Call sp_rename to change Table_A to Table_D, then again to change Table_B to Table_A.
  7. From the high water mark, write from Table_C to the newly-renamed Table_A.
  8. My favorite part: Drop Table_C, Table_D, and the trigger.

There are caveats to this method, of course, but they have been acceptable for my situations. They are:

  • The table is unavailable (non-existent, really) between the two renames in Step 6. This is an extremely brief window, but it does need to occur. Also, in order to apply a trigger, the table needs to be briefly locked, which may present a problem.
  • Step 7 is present so that changes between Steps 5 and 6 are carried over to the new table. However, these can occur after the new table is active following Step 6, meaning that the following scenario is possible:
    • A row is updated in Table_A, and the change is carried over to Table_C.
    • The renames occur.
    • The same row is updated in the new Table_A.
    • Th second change is overwritten with the first change.

If the table you wish to migrate has a considerable number of updates and deletes, then this solution may present a data integrity problem. However, for insert-heavy tables, it has proven to work very well. Also, a second trigger on the new table and some additional logic could circumvent the second issue I described, depending on your situation.

So there you go – a use for triggers.

Godspeed!

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Running PowerShell files in SQL Operations Studio

As I’ve used SQL Operations Studio more and more, I’ve also been finally using PowerShell in more situations. Given that I like the editor and that there’s a built-in terminal, I’ve been running those in my Ops Studio instance. But for a while I didn’t have a slick way of running an entire PowerShell file in the terminal. Usually, I’d just Ctrl+A/Ctrl+C/Ctrl+V, which is a bit awkward.

But among all the other ways you can customize Ops Studio, you have a lot of control over the key mappings. One way to edit these mappings is to pull up the Command Pallette (Ctrl+Shift+P) and start typing “key”, and you’ll see “Preferences: Open Keyboard Shortcuts”. You’ll also see it mentions the Ctrl+K/Ctrl+S shortcut. This will bring you to the basic Keyboard Shortcuts window, where you’ll need to click “keybindings.json”. Either way, just like Ops Studio’s overall settings (and VSCode’s, for that matter), you get a JSON file you can now tweak. Actually, two of them, with the defaults on the left and your own settings on the right.

Here’s the mapping I’ve added:


{
"key": "shift+f5",
"command": "workbench.action.terminal.runActiveFile",
"when": "editorTextFocus && editorLangId == powershell"
}

The effect of this is that pressing Shift+F5 while focus is on your PowerShell script file will cause Ops Studio to run that file in the terminal window. As an old SSMS and Visual Studio user, F5 seemed natural to me, and I noticed that Shift+F5 wasn’t already taken.

Note that this runs the file, not necessarily what you have in the window. So you may want to precede this with Ctrl+S while you’re working.

My gratitude to ck (twitter|blog) for pointing me in the right direction here. When it comes to either Ops Studio or PowerShell these days, I just assume he’s smarter than me.

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Tigers in the Rain

This is the first in what may become a series of anecdotal posts about what I’ve learned as a coach and how I think it translates to becoming a good manager…

After the match, my brother told me he knew how it was going to go when he saw them in warm-ups. The other team, he said, looked like they didn’t want to be there, shuffling around half-heartedly in the drizzle. In contrast, our girls were all smiles.

They’d been there before.

During the previous season, the TC Tigers hosted Shelbyville, a larger nearby school and a fierce rival. The rain came down in buckets that night. It was their last season on the grass, and the field held up surprisingly well. So did the girls, who beat the Golden Bears 3-1.

I’d never seen a match played in those conditions… until that night at the 2017 Sectional championship. At one point, they had to call the match on account of lightning, and the teams were sent off to the locker rooms to wait it out. But it eventually resumed, and so did the dogfight. Heritage Christian may have come into the game as heavy favorites, but our girls held their own and held the score 0-0 through regulation and two overtimes.

Then they won the shootout. And the hardware.

When he shared his observation with me afterward, I realized the team had achieved something else as well. Not only could they play well in the rain, they believed they could play well in the rain. And I also realized that it’s up to me to keep that belief alive.

We’re preparing them for a new season now. Only seven of the girls on the current roster were part of that Shelbyville game. That doesn’t matter, though. I’ve brought up those rain matches a couple of times in the off-season, when I’ve had a mix of those who were there and those who weren’t. I’d get them going, and then let the veterans reminisce about what it was like to play in those matches and to come out on top. And let the rookies soak it in.

The girls are going to win some and lose some. That’s the nature of the game. But if it rains during a match this season… well, I almost feel sorry for the other team. Are they that much better than every other team in the rain? Maybe not. But they believe they are that much better – even the girls who weren’t at those two matches.

A development team won’t ever be asked to write code outside in the rain. But they’ll have their own rain matches. A production outage, a performance issue, an angry customer… who knows what the situation will be? But there will inevitably be something – some bugaboo that they’ll be able to overcome once or twice. It’s up to the manager to spot those successes and capitalize on them. It’s up to the manager to nudge the team toward embracing them and allowing them to become part of its identity. It might take nothing more than a “Remember when…” at a team lunch. Whatever it takes, though, the important thing is to gently – imperceptibly – encourage them to believe in themselves, and in each other. Especially when the rain comes.

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tsqllint

My PASS local group, IndyPASS, has its monthly meeting tonight. At my insistence, first-time presenter Nathan Boyd is showing off a SQL tool called tsqllint. Nathan, a coworker of mine at Salesforce, is the leading developer behind this GitHub project.

A lint (or linter), if you didn’t know, “analyzes source code to flag programming errors, bugs, stylistic errors, and suspicious constructs” (wikipedia). This one is designed specifically for T-SQL, is highly configurable, and includes a Visual Studio Code extension. What more could you want, right? If you want cleaner T-SQL code out of your developers, with less hassle on the part of your reviewers, it’s definitely worth your time.

If you’re in the area, keep in mind there’s a location change tonight. While IndyPASS usually meets at Virtusa, 1401 North Meridian (formerly Apparatus), this month’s meeting is at Moser Consulting in Castleton. As usual, doors open at 5:30pm, and we’ll turn it over to Nathan by about 6:15pm.

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T-SQL Tuesday #104

My thanks to Bert Wagner and his chosen topic for T-SQL Tuesday, Code You Would Hate To Live Without. It was just enough of an excuse to dust off the cobwebs here and get back to posting.

Anyway, since half of my time is spent in C#, I thought I’d venture into that world for my response. I’ll share a couple of common extensions that I include in most of my projects. Extensions, as their name implies, extend the functionality of existing objects. Here is a code snippet with a couple of extensions I typically add:

namespace myproj.Extension
{
  public static class Extensions
  {
    public static bool In(this T val, params T[] values) where T : struct
    {
      return ((System.Collections.Generic.IList)values).Contains(val);
    }

    public static object ToDbNull(this object val)
    {
      return val ?? System.DBNull.Value;
    }

    public static object FromDbNull(this object val)
    {
      return val == System.DBNull.Value ? null : val;
    }
  }
}

The first method enables me to easily search enumerations for a given value. For example, if I’ve defined this enumeration:

namespace myRacingProject.Enum
{
  public enum Series
  {
    None = 0,
    Indycar = 1,
    IndyLights = 2,
    ProMazda = 3,
    Usf2000 = 4
  }
}

Then I could use the extension like this:

if (mySeries.In(Enum.Series.ProMazda, Enum.Series.Usf2000)) myChassis = "Tatuus";

As for the other two methods, well… When is a null not a null? When it’s a System.DBNull.Value, of course! SQL Server pros who have spent any time in the .NET Framework will recognize this awkwardness:

var p = new System.Data.SqlClient.SqlParameter("@myParam", System.Data.SqlDbType.Int);
p.Value = (object)myVar ?? System.DBNull.Value;

With the extension, the second line becomes:

p.Value = mVar.ToDbNull();

Similarly, when reading, this:

var myInt = (int?)(myDataRow[myIndex] == System.DBNull.Value ? null : myDataRow[myIndex]);

Becomes this:

var myInt = (int?)myDataRow[myIndex].FromDbNull();

They’re not earth-shattering improvements, but my real point is that extensions are an often-overlooked feature that can improve your quality of life as a developer. Anytime you find yourself writing the same bit of code over and over, especially if that bit is rather unsightly, you might consider making it an extension.

Want to know more? Here ya go: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods

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The 2017 Summit

As I adjust poorly to the three-hour time difference in Seattle this morning, I thought I’d share a few highlights of this week that are personal to me:

The Panel Sessions

I had a hand in bringing three panel sessions to the Summit this year, on Data Visualization, PowerShell, and Data Systems at Scale. I’m really looking forward to the discussions that emerge from these. If you plan on attending them, keep in mind that we’re using the #visualization, #powershellhelp, and #scale channels on sqlcommunity.slack.com as a way to take questions. Feel free to join the conversation there.

My Own Survey

There are plenty of ways to provide feedback to the people behind the Summit. But as I become more and more involved as a program committee manager, I want to give attendees a more direct, personal, and open-ended way to share your opinions. I will caution you, though – this is my own initiative and not part of PASS. I intend to use this feedback for the benefit of PASS and the Summit, but I make no promises about what I share and with whom. You’ll just have to trust me. And if you don’t? Hey, don’t fill out the survey! But if you want to help me help make the Summit better, here it is: Take My Survey

And thanks for your help!

My Own Session

It’s almost been an afterthought, but yeah, I’m presenting a session at the Summit this year. I didn’t quite plan on it, but I’m glad it’s happening. It’s targeted at developers, and – like nearly every session I present – it’s focused on making apps faster. So, if you’re interested in app performance, and you’re still around for the very last session of the conference, come see me talk about the .NET Framework’s SqlClient namespace in room 2AB!

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PASS Local Groups

I’m speaking tomorrow evening at Michiana PASS. What’s my topic? Performance, of course! Actually, it’s about querying partitioned tables. Quickly. Because that’s how I roll.

But that’s not my point today.

Like any good technical community, the success of PASS doesn’t come from the top. Local Groups are the heart of PASS. If SQL Server is relevant to your job, become a part of your PASS Local Group. Or start one, if necessary. Share what you know, encourage your peers, and contribute to the community.

And if public speaking is something you wish you could do better, presenting in front of your Local Group is a safe way to dip your toe in those waters. I present a technical session about once a year to IndyPASS. In fact, I’ll be back in September. I’m also now starting to branch out to other Local Groups, like Michiana, to help them grow. As much as I enjoy taking part in SQLSaturdays, I think I might like this more.

Godspeed,

J

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#PASS24HOP

In the past couple of years, I’ve had the opportunity to speak at a few SQLSaturdays, and presented to my local chapter, IndyPASS, a couple of times. I gained a new experience a few weeks ago, one that I had no idea would be so timely. I presented one of my sessions to YooperPASS, a new chapter in the upper peninsula of Michigan. This session was my first online session for PASS. I’ve presented online before at Salesforce, but that was to an internal audience. This was a new session, presented for the first time, to a bunch of strangers. Fortunately, the YooperPASS folks are very welcoming, and I think it went very well.

I mentioned this was timely, though, didn’t I? Well, that’s because I’ll be giving my second ever PASS virtual session on Thursday, the 20th. I’m a part of the 24 Hours of PASS: Summit Preview 2017! The same session I gave to YooperPASS, A Guided Tour of the SqlClient Namespace, will also be part of this webinar event. Because I’ll be presenting this session to a much wider audience now, I’d like to expand on my approach to this session.

First, I call it a “Guided Tour” because I’m cherry-picking those areas that I think deserve some special attention. A more comprehensive session would be impractical. So I had to cut things off somewhere. What made the cut are four topics that have valuable specific takeaways. A good technical session should give attendees something today they can put into practice tomorrow. I’d like to think I accomplished that with these topics.

Second, my choice of topics also gives me a chance to get across a broader message about how to scale ADO.NET code. Performance is always a focus of mine, and my experience has taught me that there is frequently a trade-off between application code and the database. One piece of code may perform better than another under a microscope, but its effect on overall system performance may actually be worse. In this session, I try to draw attention to this trade-off.

Finally, this is my attempt at an introductory session on an often-overlooked topic. Let’s face it, ADO.NET has been around a while. Because of that, I think the information available on it is inconsistent. StackOverflow didn’t exist until long after ADO.NET was introduced. Yes, there are some fine older resources on ADO.NET, but enterprises have changed a lot since many of them were written. Most current resources focus on Entity Framework, which is arguably just an abstraction layer over ADO.NET. So my session is intended to close the gap.

Anyway, I’m looking forward to being a part of this 24 Hours of PASS. If you tune into my hour, I hope it’s worth your time.

Godspeed,

J

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