In Structured Streaming, checkpoints store state information (offsets, progress, and metadata) needed to resume a stream after a failure or restart.

Correct usage:

Set the checkpointLocation option when writing the streaming output:

streaming_df.writeStream

.format('delta')

.option('checkpointLocation', '/path/to/checkpoint/dir')

.start('/path/to/output')

Spark uses this checkpoint directory to recover progress automatically and maintain exactly-once semantics.

Why the other options are incorrect:

A/D: recoveryLocation is not a valid Spark configuration option.

B: Checkpointing must be configured in writeStream, not during readStream.

PySpark Structured Streaming Guide --- Checkpointing and recovery.

Databricks Exam Guide (June 2025): Section ''Structured Streaming'' --- explains checkpointing and fault-tolerant streaming recovery.