tasks/online-compute/FlinkSQL/flinksql_001_en/task.md

metadata

id: online-compute_FlinkSQL_flinksql_001
name: Order Stream and Payment Stream Interval Join
category: online-compute/FlinkSQL
timeout_seconds: 600
modality: pure-text
engine: flink-sql

Prompt

I need you to write a Flink SQL that uses the built-in datagen connector to simulate an order stream and a payment stream, performing an Interval Join on order_id, and writing matched records directly to the console.

Business Background and Objective: Simulate an order stream and a payment stream using two datagen built-in tables, each generating 100 million records. The order_id and user_id in the order stream range from 1 to 1,000,000, and the order_id in the payment stream also ranges from 1 to 1,000,000. Both tables use LOCALTIMESTAMP as the event time and set a 5-second watermark delay.

Perform an Interval Join on the two tables using order_id, matching only records where the payment time falls within 5 minutes after the order time. Upon a successful match, output the original fields directly to the console table, including order_id, user_id, pay_amount, the order time, and the payment time.

Source Table Definitions:

• orders_source (order stream, datagen connector):

  • order_id INT: Order ID, randomly generated in the range 1–1,000,000
  • user_id INT: User ID, randomly generated in the range 1–1,000,000
  • order_time: Uses LOCALTIMESTAMP to generate event time, with a WATERMARK delay of 5 seconds
  • Generation rate: rows-per-second = 1000

• payments_source (payment stream, datagen connector):

  • order_id INT: Order ID, randomly generated in the range 1–1,000,000
  • pay_amount DOUBLE: Payment amount, randomly generated in the range 1–100,000
  • pay_time: Uses LOCALTIMESTAMP to generate event time, with a WATERMARK delay of 5 seconds
  • Generation rate: rows-per-second = 1000

Output Table Definition:

• console_output (print connector):
  • order_id INT
  • user_id INT
  • pay_amount DOUBLE
  • order_time TIMESTAMP(3)
  • pay_time TIMESTAMP(3)

Join Logic:

• Join condition: orders_source.order_id = payments_source.order_id
• Time window: payments_source.pay_time BETWEEN orders_source.order_time AND orders_source.order_time + INTERVAL '5' MINUTE
• Note: When writing to the sink, you must handle the dual rowtime attribute conflict by applying CAST(pay_time AS TIMESTAMP(3)) to downgrade pay_time to a plain timestamp.

Output Requirements:

• Use INSERT INTO console_output to output the matched results.
• Output field order: order_id, user_id, pay_amount, order_time, pay_time