Baking · Events · Building an internal platform with baking-events from scratch: architecture and decision log

947
BAr/baking-events·posted by rase·1 hour agoOpen source

Building an internal platform with baking-events from scratch: architecture and decision log

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.

# Load test: do not jump straight to the max concurrency.
# Ramp it up, otherwise you miss the knee.
for c in 50 100 200 400 800; do
  wrk -t8 -c$c -d60s --latency http://127.0.0.1:8080/api/feed
  sleep 20
done

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.

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

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.

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.

344 comments

344 comments

· first 120 loaded
M
Kkernel_panic·2 days ago

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

456
Llinlin·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.

449
Hhuang_ke·28 minutes ago

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

436
Rrase·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.

107
Kkite·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.

410
Mmike_xu·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.

231
Mmike_xu·28 minutes ago

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

3
Bbob_chen·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.

482
Hhuang_keOP·28 minutes 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.

21
Lli_ming·2 days ago

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

392
Sswoole_lee·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.

174
Sslow_query·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.

391
Ttang_hao·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.

5
Oops_wang·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.

373
Nnikic·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.

350
Zzhu_zong·2 days ago

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

333
Ttang_hao·2 days ago

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

315
Aalice_dev·2 days ago

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

312
Aalice_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.

307
Hhuang_keOP·2 days ago

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

231
Kkite·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.

31
Nnikic·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.

58
Wwinter·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.

3
Oops_wang·2 days ago

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

1
Hhuang_ke·2 days ago

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

97
Wwinter·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
RraseMod·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.

85
Bbob_chen·just now

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

246
Rrase·12 minutes ago

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

225
Cchen_devOP·2 days ago

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

8
Bbob_chen·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
Sswoole_lee·2 days ago

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

220
Ddev_zhou·5 hours ago

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

211
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.

250
Ttang_haoOP·2 days agoedited

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

3
Kkite·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.

185
Sswoole_lee·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.

3
Ttang_hao·2 days ago

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

52
Lli_ming·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
Bbob_chen·28 minutes ago

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

208
Wwinter·2 days ago

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

231
NnikicMod·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.

206
Ddev_zhou·2 days ago

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

119
Rrase·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.

3
Ddev_zhouMod·2 days ago

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

200
Hhuang_keOP·1 hour 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.

139
Rrase·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.

195
Rran_bo·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.

194
Bbob_chen·2 days ago

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

185
Llinlin·2 days ago

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

170
Oops_wangOP·2 days ago

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

1
Ttang_hao·2 days ago

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

164
Bbob_chen·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.

161
Rran_bo·2 days ago

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

143
Zzhu_zong·2 days ago

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

348
Zzhou_yi·2 days ago

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

36
Sswoole_lee·2 days ago

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

133
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.

132
Kkernel_panic·28 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.

71
Zzhou_yi·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.

68
Nnikic·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.

64
Nnikic·2 hours ago

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

151
Sslow_queryOP·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
Kkernel_panicMod·2 days ago

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

30
Zzhou_yi·2 days ago

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

8
Kkernel_panic·2 days ago

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

62
Aalice_devOP·just nowedited

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

1
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.

2
Hhuang_ke·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.

26
LlinlinMod·2 days ago

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

1
Ttang_hao·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
Wwinter·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.

36
Nnikic·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.

19
Wwinter·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.

12
Zzhu_zong·just nowedited

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
Mmike_xu·28 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.

400
Zzhou_yi·28 minutes ago

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

12
Ttang_hao·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.

19
Oops_wang·2 days agoedited

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

476
Rran_boMod·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.

64
Mmike_xuOP·2 days agoLevel 6

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.

468
Cchen_dev·3 minutes agoeditedLevel 6

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

97
Llinlin·2 days agoLevel 6

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.

34
Nnikic·2 days ago

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

49
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.

45
Rrase·2 days agoeditedLevel 6

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.

207
Llinlin·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.

4
Zzhou_yi·2 days agoLevel 6

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

4
Ttang_hao·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.

17
Rran_bo·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.

11
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.

78
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.

9
Hhuang_keMod·2 days ago

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

9
Ddev_zhou·5 hours ago

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

31
Rran_bo·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.

77
Lli_ming·2 days ago

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

9
Nnikic·1 hour 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.

7
Kkernel_panic·12 minutes ago

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

4
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.

313
Rrase·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.

3
Nnikic·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.

3
Zzhu_zong·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.

2
Sswoole_lee·12 minutes ago

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

208
Ddev_zhou·2 days ago

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

345
Zzhou_yiOP·28 minutes agoedited

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

41
RraseOP·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.

21
Sswoole_leeOP·12 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.

435
Sslow_query·2 days agoedited

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

246
Rrase·5 hours ago

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

76
Lli_ming·2 days ago

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

449
Hhuang_ke·2 days ago

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

388
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.

2
Lli_ming·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.

188
Lli_ming·2 days ago

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

2
Kkite·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
Cchen_dev·2 days ago

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

1
Oops_wang·2 days ago

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

11
Wwinter·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
Sswoole_lee·2 days ago

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

1
Lli_ming·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.

1

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