When compiling/running relatively simple queries that construct JSON objects it seems like the query engine is re-computing function calls instead of using the actual value when extracting JSON data.

For example, given the query:

WITH RECURSIVE iter AS

(

	SELECT 1 AS 'i'

	UNION 

	SELECT i + 1

	FROM iter 

	WHERE i < 10

),

json_data AS 

(

	SELECT

		JSON_OBJECT(

			'UUID', UUID()

		) AS 'Data'

	FROM iter 

)

SELECT

	JSON_EXTRACT(jd.`Data`, '$.UUID') AS 'Extracted',

	jd.`Data`

FROM json_data jd

you would expect the `Extracted` value to be the same as the value that was computed in the `Data` JSON_OBJECT, but it is actually different.

With this query I was able to get the same results for iter generating numbers up to 1,000,000, although in another query that consisted of more joins then I did not see this behavior; in that case the extracted UUID was the same as the originally computed UUID.