create table tmp like paper_author;
alter table tmp add index ( `paperid` )
insert into tmp(ooo，...) select ooo,... from paper_author
query ok, 35510600 rows affected (9 min 24.99 sec)
records: 35510600 duplicates: 0 warnings: 0
rename table paper_author to tmp2, tmp to paper_author;
drop table tmp2;