Test case by Steve Summers :

create table test(id int, title varchar(50));

commit;

create index test1 on test computed by (id +1);

commit; // There is not an issue creating two computed indexes in the same transaction, so this commit is optional.

create index test2 on test computed by (id +2);

commit;

drop index test1;

// If you add a commit here, everything is fine.

drop index test2;

commit;

insert into test values(1,'test'); -- Error, file handle is invalid.