very wrongg

error:
#1436 - Thread stack overrun: 6892 bytes used of a 131072 byte stack, and 128000 bytes needed. Use 'mysqld --thread_stack=#' to specify a bigger stack.

BEGIN
    DECLARE pid, gid INT;
    DECLARE done INT DEFAULT 0;
    DECLARE pcity, gcity VARCHAR(64);
    DECLARE gcur CURSOR FOR SELECT * FROM `guests`;
    DECLARE pcur CURSOR FOR SELECT `id`, `city` FROM `people` WHERE `id` = gid;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
    OPEN gcur;
    REPEAT
        FETCH gcur INTO gid, gcity;
        OPEN pcur;
        FETCH pcur INTO pid, pcity;
        IF gcity <> pcity THEN
            UPDATE `guests` SET `city` = pcity WHERE `id` = gid;
        END IF;
        CLOSE pcur;
    UNTIL done END REPEAT;
    CLOSE gcur;
END