Vue · Remote · Those easily-missed type details in vue-remote

237
VUr/vue-remote·posted by zhou_yi·32 minutes agoReviewPinned

Those easily-missed type details in vue-remote

Most vue-remote articles stop at "how to use it" and never cover "when not to use it". This is an attempt at the second half.

Order of investigation, by return on effort: 1. Check downstream latency first — usually it is not your problem 2. Then pool hit rate and wait-queue length 3. Only then GC and allocation 4. Suspect the framework last

One last trap: in container environments remember to adjust the memory-related parameters in step. Otherwise the host limit and the process expectation disagree, and the symptom is intermittent, unreproducible failure.

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.

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".

61 comments

61 comments

M
Sslow_query·just now

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.

453
Kkernel_panic·1 hour ago

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

354
Hhuang_ke·2 hours 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.

319
Hhuang_ke·2 days 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.

488
Rrase·2 days ago

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

16
Sswoole_lee·2 days ago

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

1
Kkernel_panic·2 days ago

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

56
Ddev_zhou·1 hour ago

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

144
Sswoole_leeMod·2 days ago

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

89
Oops_wang·2 hours ago

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

7
Mmike_xuOP·2 days 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.

137
Oops_wang·2 days 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.

59
Sswoole_lee·5 hours 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.

100
Oops_wangOP·28 minutes agoedited

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

99
Rrase·5 hours ago

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

154
Cchen_dev·2 days ago

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

1
Zzhou_yi·2 days 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.

186
Lli_ming·2 days ago

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

68
Rrase·3 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.

62
Hhuang_ke·just now

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.

55
Wwinter·12 minutes ago

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

272
Cchen_dev·2 days 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.

31
Kkernel_panic·2 days 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.

57
Bbob_chenMod·just now

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

34
Mmike_xuOP·3 minutes ago

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

327
Sswoole_lee·28 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.

359
Sswoole_lee·2 hours ago

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

320
Cchen_dev·2 hours ago

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

319
WwinterOP·12 minutes ago

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

319
Llinlin·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.

1
Zzhu_zong·2 days ago

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

156
Zzhu_zong·3 minutes agoedited

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

65
Zzhu_zong·2 days agoedited

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.

4
Sslow_query·2 days ago

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

443
Hhuang_keMod·12 minutes ago

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

311
Sslow_query·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.

166
Rrase·12 minutes ago

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

318
Cchen_dev·28 minutes ago

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

7
Rrase·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.

291
Llinlin·2 days ago

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

251
Oops_wang·1 hour 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.

148
Llinlin·2 hours agoedited

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

126
Sslow_queryOP·2 days 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.

156
Rrase·2 days ago

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

12
Llinlin·just nowedited

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

89
Mmike_xu·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.

86
Llinlin·2 days ago

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

31
Aalice_dev·2 days agoedited

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.

28
Rrase·yesterday

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

26
Cchen_dev·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.

25
Sslow_query·just nowedited

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.

21
Zzhou_yi·28 minutes ago

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

11
Aalice_dev·2 days agoedited

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.

486
Nnikic·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.

4
Kkernel_panic·yesterdayedited

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.

112
Nnikic·2 days 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.

6
Oops_wang·2 days ago

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

3
Kkite·3 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.

1
Kkernel_panic·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
Ddev_zhou·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.

1
Ddev_zhou·2 days ago

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

1

This is the post detail page /en/c/vue-remote/post/p0. 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 →