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

iOS · Open source · Postmortem: how we exhausted the connection pool in ios-opensource

12
IOr/ios-opensource·posted by kite·3 days agoOpen source

Postmortem: how we exhausted the connection pool in ios-opensource

Some background first. Our setup is ios-opensource plus three downstream services, seven figures of daily requests, peaking around nine in the evening.

We also fixed monitoring along the way: replaced average-based alerts with percentiles and split them per endpoint. False alerts dropped by about seventy percent and the on-call rotation visibly cheered up.

Keep it and wait for an official fix44%
Switch to a third-party option now28%
Fork and maintain it ourselves17%
Write an adapter layer and wait11%

20 votes total

5 comments

5 comments

M
Sswoole_lee·28 minutes ago

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

510
Wwinter·2 hours ago

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

396
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.

333
Hhuang_ke·12 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.

192
Zzhou_yiOP·28 minutes ago

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

32

This is the post detail page /en/c/ios-opensource/post/p10. 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 →