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Monorepo Frontend · Q&A · Building an internal platform with monorepo-frontend-qa from scratch: architecture and decision log

18
MFr/monorepo-frontend-qa·posted by winter·3 hours agoTutorial

Building an internal platform with monorepo-frontend-qa from scratch: architecture and decision log

Short version: monorepo-frontend-qa needs almost no tuning at small and medium scale — the point where it starts to hurt is much further out than most people assume. Full measurements below.

The first thing was to collapse the variables. We were changing config and upgrading the version at the same time, and afterwards nobody could say which change caused what. We rolled back to moving one variable at a time, re-ran three times, and only then did the curve settle. Tedious, but not skippable.

Worth noting: the official docs do cover this, just in a very inconspicuous spot. I only found it reading the source comments, where the author explains the reasoning — roughly "so that it degrades into predictable behaviour in extreme cases".

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10 comments

10 comments

M
Wwinter·just now

Sharing our numbers, 8 cores 16GB, same scenario:

| Concurrency | P50 | P99 |
|---|---|---|
| 200 | 12ms | 88ms |
| 500 | 31ms | 340ms |

P99 clearly collapses at 500 concurrency, which lines up with your knee point.

442
Oops_wang·1 hour ago

I just read the monorepo-frontend-qa source — the author actually explains the reasoning in a comment, roughly "so that it degrades into predictable behaviour in extreme cases".

66
Zzhu_zong·3 minutes ago

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

177
Sslow_query·28 minutes ago

There is actually a simpler fix that needs no architecture change: move this check up to the gateway and the problem disappears. The cost is one extra lookup at the gateway.

289
Sslow_query·just nowedited

Agreeing with the above. One addition: with this option enabled the GC count in your metrics doubles, so adjust the alert threshold at the same time or it will keep firing.

435
Hhuang_keOP·3 minutes ago

We have run this in production for two years without hitting it. That said, we never reached this scale, so our experience is not really evidence here.

5
Llinlin·28 minutes ago

One counter-example: below monorepo-frontend-qa 7.4 the semantics of that code are different, so do not copy it verbatim. We got burned in staging and rolled back once.

79
Cchen_dev·yesterday

Can you give a minimal reproduction? I ran it locally for ten minutes and could not reproduce on macOS with the latest version.

123
Cchen_dev·3 minutes ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

8
Wwinter·12 minutes ago

A question: what changes in a container with a 512Mi memory limit? That is how we run it in production.

3

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