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Capacitor · Ops · Cut our capacitor-ops build from 4 minutes to 40 seconds with these 5 changes

10
CAr/capacitor-ops·posted by mike_xu·5 minutes agoTranslation

Cut our capacitor-ops build from 4 minutes to 40 seconds with these 5 changes

Short version: capacitor-ops 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.

On trade-offs, my view is this: if nobody on the team owns this area long-term, do not introduce a second mechanism. With two coexistence you first have to work out which one is even in play when things break, and that costs far more than the performance you saved.

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".

Nnews.ycombinator.comExternal link · opens in a new tab
6 comments

6 comments

M
Wwinter·12 minutes ago

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.

31
Bbob_chen·just now

Thanks for sharing real numbers — far more useful than the articles that only cover concepts.

15
Wwinter·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.

5
Oops_wang·1 hour ago

Saved. I am reworking this area this week — this saves a lot of wrong turns.

406
Rrase·just now

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.

353
Ddev_zhou·3 minutes ago

This matches what we see in production. We only hit it past 3k QPS; the earlier load tests showed nothing — the test traffic was too clean, with no long-tail requests.

5

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