Operators execute actions:
PythonOperator: Run Python functionsBashOperator: Execute shell commandsSnowflakeOperator: Run Snowflake queriesS3ToSnowflakeOperator: Transfer data between systems
Sensors wait for conditions:
S3KeySensor: Wait for a file in S3ExternalTaskSensor: Wait for another DAG's taskSqlSensor: Wait for a query to return rows
Sensors use "poke" mode (checks periodically) or "reschedule" mode (frees worker between checks). Reschedule mode is more efficient for long waits.