OFOffline First · Open source
Community homeHot discussions Latest posts Best of Knowledge base Resources About

Offline First · Open source · offline-first-opensource under load on an 8-core 16GB box — full benchmark scripts included

62
OFr/offline-first-opensource·posted by winter·6 hours agoJobs

offline-first-opensource under load on an 8-core 16GB box — full benchmark scripts included

Short version: offline-first-opensource 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.

What genuinely surprised me was the tail. The average looked great while P99 jumped by an order of magnitude past some threshold. The cause was not offline-first-opensource itself but our upstream connection reuse — the load test traffic was too clean and hid the long-tail requests.

Ggithub.comExternal link · opens in a new tab
21 comments

21 comments

M
Rran_bo·3 minutes ago

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

342
Rran_bo·2 days ago

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

20
Hhuang_ke·5 hours ago

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

260
LlinlinOP·2 days ago

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.

169
Mmike_xu·28 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.

142
Sswoole_lee·5 hours 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.

123
Lli_ming·2 days agoedited

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.

297
Oops_wang·2 days ago

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

30
Oops_wang·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.

61
Zzhu_zong·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.

7
Sswoole_lee·1 hour ago

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

1
Zzhou_yiOP·28 minutes ago

This is not a offline-first-opensource problem, it is a usage problem. The docs say this API is not thread-safe and you must lock around it yourself.

1
Bbob_chenOP·just now

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

76
Oops_wang·28 minutes ago

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

132
Cchen_dev·3 minutes ago

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

128
Cchen_dev·12 minutes ago

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.

123
Wwinter·3 minutes ago

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

78
Kkernel_panic·2 days ago

This is not a offline-first-opensource problem, it is a usage problem. The docs say this API is not thread-safe and you must lock around it yourself.

3
Aalice_dev·2 days ago

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

32
Mmike_xu·1 hour ago

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

4
Mmike_xu·1 hour ago

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

15

This is the post detail page /en/c/offline-first-opensource/post/p2. Posts and comments are generated deterministically from a seeded PRNG, so the same post always renders the same content and the link can be shared, reloaded and indexed. In production this page reads MySQL for the post, Redis for hot-post caching, and fetches the whole comment tree in a single query on the path column.

See the database schema →