Answer: Checkpointing and Write-ahead Logs

In Structured Streaming, Spark uses checkpointing and write-ahead logs to record the offset range of the data being processed in each trigger. Checkpointing is a mechanism to persist the intermediate state of the streaming computation, thus enabling fault-tolerance by recovering this state and starting from where it left off in case of a failure. Write-ahead logs ensure that any modifications to the state are saved before the state is updated, thus providing reliability and consistency in tracking the exact progress of the processing. This combination ensures that Spark can reliably track and handle any kind of failure by either restarting the process or reprocessing the data.

Author: LeetQuiz Editorial Team