Limit for WHERE IN in MySQL?

Question

MySQL

I once read somewhere that there is a limit on the input data of the WHERE IN () construct.
Can someone tell me what the limit is?

SELECT * 
FROM  `A` 
WHERE  `id` 
IN (
SELECT id
FROM `B`
WHERE row2 =1
)

Tried to substitute for the test in IN 300 000 id. No mistakes. It is more difficult to check, since such tests create a load on the working project.