Vue Community · Ten Vue anti-patterns — how many are you guilty of?

56
Vr/vue·posted by rase·6 hours agoTranslation

Ten Vue anti-patterns — how many are you guilty of?

Short version: Vue 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.

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".

-- The query that broke: a full scan over 20M rows.
-- A composite index took P99 from 1.8s down to 42ms.
SELECT id, title, created_at
  FROM posts
 WHERE community_id = ?
   AND status = 1
 ORDER BY score DESC
 LIMIT 20;

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 Vue itself but our upstream connection reuse — the load test traffic was too clean and hid the long-tail requests.

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.

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.

22 comments

22 comments

M
Oops_wang·2 days ago

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

417
Sslow_query·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.

376
Mmike_xu·5 hours ago

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

369
Mmike_xu·yesterday

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

83
Rrase·3 minutes ago

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

273
Zzhou_yi·2 days ago

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

272
Hhuang_keOP·28 minutes ago

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

24
Sslow_query·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.

182
Ddev_zhou·28 minutes ago

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

342
Nnikic·just now

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.

469
Zzhou_yi·28 minutes agoedited

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

451
Nnikic·28 minutes agoedited

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

176
Sswoole_lee·2 hours ago

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

10
Cchen_devMod·2 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.

41
Nnikic·2 days 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.

191
Bbob_chen·2 days ago

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

81
Llinlin·yesterday

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

77
Oops_wangOP·28 minutes agoedited

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.

1
Aalice_dev·yesterday

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.

22
Aalice_dev·3 minutes agoedited

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

10
Wwinter·28 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.

1
Llinlin·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.

1

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