The Setup: Great News, Team!

Liz: Mary, Jess, did y’all hear that our team is picking up responsibility for another app?

Mary: Whaaaaaat? What app is it?

Liz: ‍Something about a ... sequence of numbers? I haven’t seen it before. It’s an internal app, whoever wrote it is gone, and the people using it are complaining that it is slow. ‍

Jess: .... What language is it in?

Liz: unclear.

Jess: and it’s ours... why?

Liz: uh, reasons?

Mary: Guess I’ll... pull down the repo and spend a week getting it running?

Jess: The slowness is in production, who knows whether we’ll ever reproduce it locally.

Liz: Oh! but I do know: it’s instrumented using OpenTelemetry.

Jess: Oh great! Maybe we can diagnose that slowness right now, before we even clone the repo.

Mary: Oh, telemetry, great! we’ll get to see how it’s used, and the traces will show us what’s really happening inside.

Jess: We’ll know what to look for in the code. And we can see what happens after we change it.

Liz: My thoughts exactly. We have observability, so don’t have to fear making a change.

Mary: Can we see the app now?

Jess: Yeah!

Liz: I’ll paste the URL in the chat.

Mary: Got it. Sharing my screen.

Jess: Sequence of numbers, it says. Let’s push Go!

Liz: Those are numbers all right.

Jess: I see what they mean about slowness, it’s getting slow now.

Liz: Hmm, hit stop.

Jess: Is it doing anything?... Oh, a stop sign appeared

Liz: Try pushing go again.

Jess: Will it be slow immediately this time?

(Mary hits go, the sequence restarts)

Jess: Oh, it was fast again, and now it’s slowing down.

Liz: Like it’s getting slower as it gets farther into the sequence.

Mary: Let me look at these requests in the network tab of the browser debugger.

Liz: Sure enough, they take longer as they go on.

Mary: Now I want to see what’s happening on the server for each of those requests.

all three in unison: To Honeycomb!