tasks/online-compute/FlinkSQL/flinksql_009_en/task.md

metadata

id: online-compute_FlinkSQL_flinksql_009
name: Tumbling Window PV/UV Statistics
category: online-compute/FlinkSQL
timeout_seconds: 600
modality: pure-text
engine: flink-sql

Prompt

I need you to write a Flink SQL that uses a datagen built-in table to simulate a user click stream, computes PV and UV per page over a window, and writes the results to the console.

Business Background and Objective: Simulate a user click stream using a datagen built-in table (user_id ranging from 1–1000, page_id ranging from 1–50, 10,000 records per second). Compute the PV (COUNT(*)) and UV (COUNT(DISTINCT user_id)) per page over a 1-minute tumbling window. Output the results (window start, window end, page_id, pv, uv) to the console.

Source Table Definition:

• click_source (user click stream, datagen connector):
  • user_id INT: User ID, randomly generated in the range 1–1000
  • page_id INT: Page ID, randomly generated in the range 1–50
  • event_time: Uses LOCALTIMESTAMP to generate event time, with a WATERMARK delay of 5 seconds
  • Generation rate: rows-per-second = 10000

Output Table Definition:

• console_output (print connector):
  • window_start TIMESTAMP: Window start time
  • window_end TIMESTAMP: Window end time
  • page_id INT: Page ID
  • pv BIGINT: Page views (PV)
  • uv BIGINT: Unique visitors (UV)

Query Logic:

• Window: TUMBLE(event_time, INTERVAL '1' MINUTE) tumbling window
• Grouping: Group by page_id and the window
• PV: COUNT(*) to compute page views
• UV: COUNT(DISTINCT user_id) to compute unique visitors
• Window functions: Use TUMBLE_START / TUMBLE_END to obtain the window start and end times

Output Requirements:

• Use INSERT INTO console_output to output the results.
• Output field order: window_start, window_end, page_id, pv, uv