diff --git a/docs/static/mem-queue.asciidoc b/docs/static/mem-queue.asciidoc index 110716bacd9..a6612e40798 100644 --- a/docs/static/mem-queue.asciidoc +++ b/docs/static/mem-queue.asciidoc @@ -26,17 +26,21 @@ TIP: Consider using <> to avoid these limit ==== Memory queue size Memory queue size is not configured directly. -It is defined by the number of events, the size of which can vary greatly depending on the event payload. +Instead, it depends on how you have Logstash tuned. -The maximum number of events that can be held in each memory queue is equal to -the value of `pipeline.batch.size` multiplied by the value of -`pipeline.workers`. -This value is called the "inflight count." +Its upper bound is defined by `pipeline.workers` (default: number of CPUs) times the `pipeline.batch.size` (default: 125) events. +This value, called the "inflight count," determines maximum number of events that can be held in each memory queue. -NOTE: Each pipeline has its own queue. +Doubling the number of workers OR doubling the batch size will effectively double the memory queue's capacity (and memory usage). +Doubling both will _quadruple_ the capacity (and usage). + +IMPORTANT: Each pipeline has its own queue. See <> for more info on the effects of adjusting `pipeline.batch.size` and `pipeline.workers`. +If you need to absorb bursts of traffic, consider using <> instead. +Persistent queues are bound to allocated capacity on disk. + [[mq-settings]] ===== Settings that affect queue size