gistfile1.txt

begin;

create table varchar_table (
  blah character varying(32)
);

create table text_table (
  blah text,
  check (length(blah) <= 32)
);

\timing

-- 5.3 seconds
insert into varchar_table (select md5(random()::text) from generate_series(1, 1000000));

-- 5.7 seconds
insert into text_table (select md5(random()::text) from generate_series(1, 1000000));