SET @old_innodb_file_per_table=@@innodb_file_per_table;
SET GLOBAL innodb_file_per_table=0;
create table bug56947(a int not null) engine = innodb;
CREATE TABLE `bug56947#1`(a int) ENGINE=InnoDB;
alter table bug56947 add unique index (a);
ERROR HY000: Table 'test.bug56947#1' already exists
drop table `bug56947#1`;
drop table bug56947;