Question

DROP FUNCTION IF EXISTS my_func;
DELIMITER ||
CREATE FUNCTION my_func(arg_id INT) RETURNS VARCHAR(200)
BEGIN
    DECLARE local_id INT;
    DECLARE local_name VARCHAR(200);
    START TRANSACTION; /* <-- this is allowed */
        SELECT      id, name
            INTO    local_id, local_name
            FROM    table
            WHERE   id = arg_id
            FOR UPDATE;
        SELECT my_other_function(local_name) INTO local_name;
        UPDATE table SET name = local_name;
    COMMIT; /* <-- this is not allowed
        and yields an "Explicit or
        implicit commit is not
        allowed..." error */
    RETURN local_name;
END||
DELIMITER ;

Are return statements implicit commits?

How are you supposed to ensure that a certain function runs as a transaction?

Wrap it in a transaction?

START TRANSACTION;
    SELECT my_func(33); /* <-- no transaction statements inside the function */
COMMIT;

Start the transaction inside the function and commit?

SELECT my_func(33); /* <-- contains only the START TRANSACTION line */
COMMIT;

Also i’ve researched the issue and found some info that said something along the lines of: “statements in stored functions are not guaranteed to be executed in the declared order which can make binary logging (and implicitly replication) inconsistent”.

Answer 1

I had to use this before and it worked for me:

Option 1

SET autocommit = {0 | 1}

After you have completed what you want to do, you can re-enable it or call an explicit commit.

Option 2
To disable autocommit mode implicitly for a single series of statements, use the START TRANSACTION statement:

START TRANSACTION;
SELECT @A:=SUM(salary) FROM table1 WHERE type=1;
UPDATE table2 SET summary=@A WHERE type=1;
COMMIT;

I got this from the mysql website itself – MySQL

---

For your situation, I would think that setting autocommit to false before the function would do the trick (starting a transaction is the same thing if you look at the description of it above). That way, during the transaction, your function, it doesn’t autcommit.