The largest Italian Heritage Parade the city has ever seen will march through Fisherman’s Wharf and North Beach on Sunday, Oct. 12. And that’s saying a lot, considering it’s San Francisco’s oldest civic event, celebrating its 146th year, and the nation’s oldest Italian-American parade.  “This year is going to be the biggest parade we’ve had so far,” said Tony Passanisi, president of the nonprofit Columbus Day Celebration Committee. “We’ve had to stop taking entries.” Eighty-seven units – some containing hundreds of people – will march. It starts at Jefferson and Stockton Streets in Fisherman’s Wharf, proceeds south through North Beach on Columbus Avenue, and ends in Washington Square in front of Sts. Peter and Paul Church. Parade viewing is available throughout the route. Passanisi wasn’t sure why this year attracted so many entrants, but guessed the good weather lately or the excitement surrounding the return of Fleet Week might be reasons.