text: create table test1(i int);
  create table test2(i int);
  insert into test1 values (generate_series(1,100000));
  insert into test2 values (generate_series(1,100000));
  insert into test1 values (generate_series(2,100000));
  insert into test2 values (generate_series(2,100000));
  insert into test1 values (generate_series(3,100000));
  insert into test2 values (generate_series(3,100000));
  create table test3(i int);
  create table test4(i int);
  insert into test3 values (generate_series(1,100000));
  insert into test4 values (generate_series(1,100000));
  insert into test3 values (generate_series(2,100000));
  insert into test4 values (generate_series(2,100000));
  insert into test3 values (generate_series(3,100000));
  insert into test4 values (generate_series(3,100000));
  