Rhino comes with two types of limiter: rate limiter and queue-saturation limiter.
Rate limiter
Rate limiters limit the rate of work. It is typically used to limit the rate of incoming events, or outgoing requests.
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Rejects work when… |
the number of units used (or forced) during a given timeUnit exceeds maxRate. TimeUnit can be one second, one minute, one hour, or one day (24-hour period, not calendar day). Rhino implements rate limiters with a token bucket algorithm, where the depth property determines the bucket size. The actual bucket size is maxRate * depth. The default setting for depth is 1.0. So "50/sec" means "allow for 50 per second". When depth is 2, "50/sec" means "allow an initial burst of 100 and then 50 per second." The recommended setting for maxRate is where your CPU is around 85%. |
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Queue-saturation limiter
The queue-saturation limiter rejects work when the event-staging queue (explained in the Staging section) passes a given saturation. It provides some overload protection, by limiting incoming activities in cases where too much work is backlogged, while allowing enough headroom to process existing activities.
For example, the default configuration has the QueueSaturation
limiter configured with an allowed capacity of 85%
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With the default maximum queue size of 3000, this limiter starts rejecting new activities when 2250 or more items are in the queue (leaving 15% headroom for processing existing activities).
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Rejects work when… |
the number of items in the staging queue reaches maxSaturation, expressed as a percentage of the queue’s capacity. |
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