In which data processing stream is backpressure management implemented?

The load control mechanism (backpressure) is implemented on the consumer (subscriber) side in the data processing stream. This means that the consumer controls how much data it is willing to accept and process to avoid overloading itself and the system.

In reactive streams (e.g., RxJava, Flow in Kotlin), the subscriber requests a certain number of items from the source, and the source does not send more than requested. This achieves a balance between the producer and consumer, preventing buffer overflow and OutOfMemory errors.

Example in RxJava:

Flowable.range(1, 1000)
    .onBackpressureBuffer()
    .subscribe(new Subscriber<Integer>() {
        @Override
        public void onSubscribe(Subscription s) {
            s.request(10); // request 10 items
        }

        @Override
        public void onNext(Integer integer) {
            // process the item
        }

        // other methods...
    });

Thus, backpressure is a mechanism built into the data stream where the consumer controls the rate of data flow.