How to create a big table for performances testing

[PAscal]

Postgres

create table public.big as select * from information_schema.columns;
insert into public.big select * from public.big;
insert into public.big select * from public.big;
insert into public.big select * from public.big;
...
commit;

MySQL
create table test.big as select * from information_schema.columns;
insert into test.big select * from test.big;
insert into test.big select * from test.big;
...
commit;