What is the difference between push-based and pull-based data processing systems?

Push systems send data automatically to consumers, while pull systems require consumers to request data.

In push-based systems, producers actively send data downstream, which is common in streaming systems like Flink or Kafka producers. In pull-based systems, consumers request data when ready, such as in database queries or Spark batch reads. Push models reduce latency but require backpressure handling, while pull models provide better control over load but may introduce latency. Modern systems often combine both approaches.