that's nothing -- the talmud records a 3 year debate on one particular issue:
Rabbi Abba said that Shmuel said: For three years Beit Shammai and Beit Hillel disagreed. These said: The halakha is in accordance with our opinion, and these said: The halakha is in accordance with our opinion. Ultimately, a Divine Voice emerged and proclaimed: Both these and those are the words of the living God. However, the halakha is in accordance with the opinion of Beit Hillel.