postgres=# explain select * from csv_accounts where aid = 1;
                             QUERY PLAN
---------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=1 width=97)
   Filter: (aid = 1)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where aid < 1000;
                               QUERY PLAN
------------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=1000 width=97)
   Filter: (aid < 1000)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where aid > 1000;
                                QUERY PLAN
--------------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=499000 width=97)
   Filter: (aid > 1000)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where bid = 1;
                                QUERY PLAN
--------------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=100000 width=97)
   Filter: (bid = 1)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where bid = 2;
                                QUERY PLAN
--------------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=100000 width=97)
   Filter: (bid = 2)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where bid = 4;
                                QUERY PLAN
--------------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=100000 width=97)
   Filter: (bid = 4)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)

postgres=# explain select * from csv_accounts where bid = 6;
                             QUERY PLAN
---------------------------------------------------------------------
 Foreign Scan on csv_accounts  (cost=0.00..57105.00 rows=1 width=97)
   Filter: (bid = 6)
   Foreign File: /home/hanada/DB-fujita/CSV/pgbench_accounts.csv
   Foreign File Size: 47963070
(4 rows)