Backpressure Mode

When large amounts of events are produced by OPERA Cloud (>1.8Mb), the Streaming API begins sending events in bursts (backpressure mode), moving onto the next burst dynamically based upon the line speed.

The below animation illustrates this. The pause interval is now determined dynamically based on the line speed, which is read from the heartbeat exchange (ping and pong).

Once the backlog is cleared, the Streaming API exits backpressure mode and resumes the normal flow of events.

Pong deferral during bursts: While sending a burst in backpressure mode, the server may defer replying to client pings with pong until the current burst completes. Treat the continued flow of next messages as proof of life. For heartbeat guidance, see the heartbeat notes in Maintain a Healthy Connection and Token Lifecycle, Subscribing and Consuming Events, Replaying Events, and Retrieving the Latest Event.