Add fairness to history RPS rate limiter#10134
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| return preemptablePriority | ||
| } | ||
| callerTypePri := configs.RequestToPriority(req) | ||
| if !enabled() { |
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can this check be moved above checking Operator/Preemptable priority?
| ownershipBasedQuotaScaler, | ||
| nil, | ||
| func(string) int { return 0 }, | ||
| config.FrontendGlobalNamespaceRPS, |
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should this be HistoryGlobalNamespaceRPS ? I assume it's mostly fine to share dynamic configs, considering frontend is more lightweight, but should we document that this config is used for History RPS rate limiting as well?
| } | ||
| metrics.ServiceRequestsNamespaceFairnessDemoted.With(metricsHandler).Record( | ||
| 1, | ||
| metrics.NamespaceTag(req.Caller), |
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should we include the demoted priority value as well as a tag?
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What changed?
Add fairness mechanism to history rps rate limiter. Each namespace will have a history RPS limit quota per history host based on this formula
NamespaceQuota = FrontendRPSLimit * HistoryShardsInHost/TotalShards * Multiplier.
This multiplier is configurable through dynamic config. If a namespace's request rate exceeds this quota, those extra requests will be deprioritized. If history rps rate limiter starts to thorttle requests, these deprioritized requests will be throttled first. This will prevent unbalance load from a namespace affecting other namespaces in a history host.
Why?
To prevent noisy neighbour issues in history rps rate limiter.
How did you test it?