Order Queue Latency

Order queue latency is the delay experienced by an order while it waits in the exchange's matching engine queue before being processed. This queue is a standard part of a first-in, first-out matching system.

Even if a trader's order reaches the exchange server quickly, it may still face delays if the matching engine is busy processing a backlog of previous orders. During periods of high volatility, the length of this queue can grow rapidly, leading to significant variations in execution time.

Understanding and predicting queue latency is a vital part of low-latency trading, as it determines the actual priority of an order. It is an often-overlooked factor in the broader study of matching engine performance and execution speed.