[FLINK-23751] Testing Window Top-N after Windowing TVF

• Type: Improvement
• Status: Resolved
• Priority: Blocker
• Resolution: Resolved
• Fix Version/s: 1.14.0
• Component/s: Tests
• Labels: release-testing
• Assignee: Martijn Visser
• Reporter: Jing Zhang
• Created: 13/Aug/21 03:16
• Updated: 07/Sep/21 17:10
• Resolved: 07/Sep/21 17:10

Description

Currently, Flink not only supports Window Top-N which follows after Window Aggregation. but also supports Window Top-N follows after Windowing TVF.

The following example shows how to calculate Top 3 items which have the highest price for every tumbling 10 minutes window.

SELECT * FROM Bid;
+------------------+-------+------+-------------+
| bidtime | price | item | supplier_id |
+------------------+-------+------+-------------+
| 2020-04-15 08:05 | 4.00 | A | supplier1 |
| 2020-04-15 08:06 | 4.00 | C | supplier2 |
| 2020-04-15 08:07 | 2.00 | G | supplier1 |
| 2020-04-15 08:08 | 2.00 | B | supplier3 |
| 2020-04-15 08:09 | 5.00 | D | supplier4 |
| 2020-04-15 08:11 | 2.00 | B | supplier3 |
| 2020-04-15 08:13 | 1.00 | E | supplier1 |
| 2020-04-15 08:15 | 3.00 | H | supplier2 |
| 2020-04-15 08:17 | 6.00 | F | supplier5 |
+------------------+-------+------+-------------+

Flink SQL> SELECT *
 FROM (
 SELECT *, ROW_NUMBER() OVER (PARTITION BY window_start, window_end ORDER BY price DESC) as rownum
 FROM TABLE(
 TUMBLE(TABLE Bid, DESCRIPTOR(bidtime), INTERVAL '10' MINUTES))
 ) WHERE rownum <= 3;
+------------------+-------+------+-------------+------------------+------------------+--------+
| bidtime | price | item | supplier_id | window_start | window_end | rownum |
+------------------+-------+------+-------------+------------------+------------------+--------+
| 2020-04-15 08:05 | 4.00 | A | supplier1 | 2020-04-15 08:00 | 2020-04-15 08:10 | 2 |
| 2020-04-15 08:06 | 4.00 | C | supplier2 | 2020-04-15 08:00 | 2020-04-15 08:10 | 3 |
| 2020-04-15 08:09 | 5.00 | D | supplier4 | 2020-04-15 08:00 | 2020-04-15 08:10 | 1 |
| 2020-04-15 08:11 | 2.00 | B | supplier3 | 2020-04-15 08:10 | 2020-04-15 08:20 | 3 |
| 2020-04-15 08:15 | 3.00 | H | supplier2 | 2020-04-15 08:10 | 2020-04-15 08:20 | 2 |
| 2020-04-15 08:17 | 6.00 | F | supplier5 | 2020-04-15 08:10 | 2020-04-15 08:20 | 1 |
+------------------+-------+------+-------------+------------------+------------------+--------+

Note: Currently, Flink only supports Window Top-N follows after Windowing TVF with Tumble Windows, Hop Windows and Cumulate Windows. Window Top-N follows after Windowing TVF with Session windows will be supported in the near future.

 

 

Issue Links

• Testing discovered: FLINK-24186 Disable single rowtime column check for collect/print