Clojure · Job board · Help: clojure-jobs fails to start intermittently in containers, logs inside

212
CLr/clojure-jobs·posted by alice_dev·3 hours agoTooling

Help: clojure-jobs fails to start intermittently in containers, logs inside

It took me two weeks of on-and-off digging and plenty of wrong turns. Writing the process down as it happened so the next person spends less time.

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.

Performance44%
Maintainability28%
Ecosystem and community17%
Hiring difficulty11%

360 votes total

82 comments

82 comments

M
Kkernel_panic·just now

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

429
Zzhou_yiMod·2 days ago

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

348
Zzhu_zong·2 days ago

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

76
Oops_wangOP·2 days ago

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

140
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.

84
Zzhu_zong·2 days ago

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

395
Kkite·just now

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

367
Bbob_chen·2 days ago

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

312
Oops_wang·1 hour ago

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

310
Mmike_xu·12 minutes ago

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

305
Cchen_dev·1 hour ago

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

182
Ddev_zhou·3 minutes 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.

304
Hhuang_ke·2 days agoedited

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

257
Zzhu_zong·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.

254
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.

407
Zzhu_zongOP·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.

194
Ddev_zhou·2 days ago

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

419
Cchen_dev·2 days ago

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

135
Lli_ming·2 days ago

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

237
Kkernel_panic·2 days ago

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

236
Hhuang_ke·2 days ago

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

202
Llinlin·2 days ago

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

48
Hhuang_keMod·12 minutes ago

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

112
Sslow_query·2 days ago

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

7
Lli_mingMod·1 hour 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.

192
Rran_bo·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.

153
Bbob_chen·5 hours ago

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

119
Bbob_chen·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.

494
Rran_bo·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
Aalice_dev·12 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.

47
Hhuang_ke·2 days ago

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

450
Sslow_query·2 days ago

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

102
Kkite·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.

283
Kkite·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.

101
Ddev_zhou·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.

340
Cchen_dev·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.

189
Hhuang_keMod·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.

11
Sslow_query·5 hours 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.

15
Kkernel_panic·1 hour agoLevel 6

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

106
Hhuang_ke·just now

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

63
Nnikic·2 days agoedited

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

380
Bbob_chen·1 hour ago

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

310
Zzhu_zongMod·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.

36
Bbob_chen·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.

336
Rrase·2 days agoLevel 6

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

98
Aalice_dev·1 hour 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.

2
Sswoole_leeOP·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.

356
Zzhou_yi·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.

208
Aalice_dev·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.

3
Hhuang_ke·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.

1
Rrase·28 minutes agoedited

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

5
Wwinter·2 days ago

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

210
Sslow_queryOP·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.

99
Zzhu_zong·2 days ago

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

58
Kkite·2 days ago

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

57
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.

41
Lli_ming·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.

53
Aalice_dev·2 days ago

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

33
Ttang_hao·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.

39
Sslow_query·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.

17
Mmike_xu·3 minutes ago

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

13
Mmike_xuOP·2 days ago

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

86
Oops_wang·2 days ago

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

12
Ddev_zhou·12 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
Ddev_zhou·yesterday

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.

10
Rran_bo·2 days 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.

4
Rran_bo·yesterday

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

9
Kkernel_panic·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.

9
Llinlin·2 days agoedited

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.

326
Zzhou_yi·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.

7
Kkite·yesterday

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
Ttang_hao·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.

6
LlinlinMod·2 days ago

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

3
Sslow_query·2 days ago

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

242
Kkernel_panic·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.

2
Rran_bo·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
NnikicOP·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.

133
Hhuang_ke·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.

2
Bbob_chen·2 days ago

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

1
Bbob_chen·12 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.

1
Sswoole_lee·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
Oops_wang·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.

1

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