T-SQL Tuesday 118: Fantasy Feature

It really shouldn’t be this difficult. But it is. And that’s why we get paid. Still, it’d be nice if load-testing were easier, wouldn’t it?

Aka “hey look at us Microsoft, we want stuff!!” Because they shut down Connect and its replacement (Azure Feedback aka rebranded UserVoice) is awful. Just plain terrible. In unrelated news, I’ve never been an MVP.. wonder why? 🙄😜

Anyhoo, this month’s invitation is brought to us by the lovely and talented Kevin Chant. He asks us to fantasize about SQL Server. No, not like that Erik, get your mind out of the gutter.

And I don’t apologize. At all.

This IS a complaint. But hopefully it’s also an idea for those who are better at building stuff than me to.. ya know.. build stuff.

And shout-out to my favorite fellow blogger Shane (@SOZDBA) who’s too polite for his own good. ❤

Load Testing is HARD.

Too hard. So hard that nobody does it. At least not productively, efficiently, or willingly. About the only times that I can personally point out an instance where I’ve actually buckled down and done something roughly comparable to a true load test (which I’ll talk about in a minute), was when I was forced to do so by my managers to prove that a hardware environment upgrade hadn’t gone awry, and that our servers truly were running at least as good as, if not better than, before.

But guess what? We never really proved anything conclusively. We had inklings, feelings, warm fuzzies.. okay maybe a DiskSpd output file or two.. which indicated that things were “mostly probably pretty good and kinda sorta better.”

Why? BECAUSE IT’S FREAKING HARD.

What is “True Load Testing”?

a graphic representing software load testing
Something like that… maybe?

Glad you asked. Simply put, it’s the ability to execute these 3 steps, easily and efficiently, with minimal configuration overhead and without needing to pour agonizingly over tomes of docs:

  1. Capture and store a SQL server workload — i.e. ALL the transactions run against an instance in a given time frame — AND performance metrics from said instance while said workload was running.
  2. Run that captured workload against another SQL server instance, and capture THE SAME performance metrics.
  3. Compare results from each set of gathered performance metrics, with a concise, easy to understand rating system that tells you which instance ran better and why.

Now, could we argue that the “capturing” of #1 adds some overhead to the instance? Sure! So I’m fine with NOT gathering the performance metrics during the same window as the workload-capture. Put it off to step 2, where we replay said workload against 1 or more instances and measure the performance on them. So we could replay the same workload on the original instance, and a new one, and we’d have our two sets of measurements to compare.

Got me? Good.

The Plumbing is There

I know. I know what you’re screaming at your monitor/screen right now. “But Nate, that’s exactly what Distributed Replay is for!!”

Bruh, have you even USED Distributed Replay?!? It’s way too complicated to set up, let alone manage and operate. Remember what I said about tomes of docs? Yeah. ANGTFT.

That’s the sad part. Microsoft has built up the plumbing and scaffolding for all of this over the past few decades. But we’ve yet to see that final layer, that chrome polish and finishing touch that makes the user go “Ahhh, now THAT was an educational and enjoyable experience!”

red easy button
Staples’ trademark be damned!

Obviously when it comes to performance metrics we’ve got a huge wealth of knowledge in the system DMVs. Great! Now let’s condense and simplify those into like 4 key ratings of your instance, for those of us who aren’t Paul Randal or Glenn Berry.

Oh, 3rd party monitoring products you say? Sure! Great! Love em. Do they do what I just said? Nope. Because “it depends.” Anybody else sick of hearing that?

It Really Shouldn’t Be This Difficult

But that’s why we get paid. Because it is. And no matter how many cloud services Azure & AWS try to shove down our throats, the reality is that enterprises will continue to rely on human engineers to prove (or disprove) that NewFancyServerX is better than OldCrappyServerA for running YourTerribleSqlWorkloadZ.

Because we can’t architect perfection. And we live in the real world where business decisions and financial constraints have an actual measurable impact on our technology stack choices and roadmaps. So I’m not saying it’s inexcusable that we don’t have this — this easy, measurable, understandable toolset for performance-load-testing — yet. I’m just saying it’s mildly annoying. And perhaps a little frustrating.

With that, I think I’ve written two angry rant-y posts in a row, so I do apologize to you, dear reader (but not, and never, to Microsoft). I’ll leave you with this cute picture of my dog being ridiculous, because it always makes me smile. Til next time!

husky dog laying on back in silly position
doggo being doggo

Author: natethedba

I'm a SQL Server DBA, family man, and all-around computer geek.

2 thoughts on “T-SQL Tuesday 118: Fantasy Feature”

  1. Have you heard about Microsoft’s DEA? (Database Experimentation Assistant)

    I heard about it rather recently, and although I don’t have direct experience with it, from what I gather it seems to be that exact “chrome polish and finishing touch” that you speak of. It’s even built on top of Distributed Replay functionality.

    Liked by 1 person

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