Kudu Conditional UPSERT INTO

Question

Does Kudu support conditions on the UPDATE portion of UPSERT INTO ?

Can I provide a conditional clause to only update given values based on a comparison between the insert values and destination table? The actual use case is to update a timestamp column with the latest.

Here's the behavior as I imagine it.

CREATE TABLE my_first_table
(
  id INT,
  name STRING,
  status INT,
  PRIMARY KEY(id)
)
PARTITION BY HASH PARTITIONS 4
STORED AS KUDU;

INSERT INTO my_first_table VALUES (1, "lee", 101), (2 "shiv", 102), (3,"bob", 103);

--CONDITION FALSE, UPDATE NOT PERFORMED
UPSERT INTO my_first_table AS t 
VALUES (3, "bobby", 100) AS v 
WHERE v.status > t.status

+----+------+--------+
| id | name | status |
+----+------+--------+
| 1  | lee  | 101    |
| 2  | shiv | 102    |
| 3  | bob  | 103    |
+----+------+--------+

--CONDITION TRUE, UPDATE PERFORMED
UPSERT INTO my_first_table AS t 
VALUES (3, "bobby", 100) AS v 
WHERE v.status < t.status

+----+------+--------+
| id | name | status |
+----+------+--------+
| 1  | lee  | 101    |
| 2  | shiv | 102    |
| 3  | bobby| 100    |
+----+------+--------+

In the case where 3 does not exist, it should insert.

Is there an elegant workaround if not?

Answer 1

A solution I found was to use a LEFT JOIN and filter in the SELECT expression. So say we have an table to_upsert identical to the destination table with all our potential upserts...

INSERT INTO to_upsert VALUES (3, "bobby" 100), (5, "newgal", 600);

UPSERT INTO my_first_table
SELECT to_upsert.id, to_upsert.name, to_upsert.status
FROM to_upsert
LEFT JOIN my_first_table ON to_upsert.id = my_first_table.id
WHERE my_first_table.status > to_upsert.status OR my_first_table.id IS NULL;

SELECT * FROM my_first_table;
+----+--------+--------+
| id | name   | status |
+----+--------+--------+
| 3  | bobby  | 100    |
| 1  | lee    | 101    |
| 2  | shiv   | 102    |
| 5  | newgal | 600    |
+----+--------+--------+

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