Commit setting transaction isolation level

[Torben Koch]

Hey everybody,
I work with MySQL Workbench and I do some testing, which include setting the transaction isolation level and demonstrating dirty read, etc.
Before I start the execution of the transaction I am setting the transaction isolation level like the following example shows.

SET GLOBAL TRANSACTION ISOLATION LEVEL repeatable read;
SET SESSION TRANSACTION ISOLATION LEVEL repeatable read;
SET autocommit=0;

START TRANSACTION;
SELECT * FROM person;
COMMIT;

When I execute the transaction the first time after I change the transaction isolation level it often executes the transaction with the level which it used before. In the second run it uses the new transaction isolation level.

Do I need to commit the change of the transaction isolation level or what am I doing wrong?

Salute,
Torben