Panic Index!!!!

Hi this is my code of sql select

SELECT
     a.f_codigo_cliente,
     a.f_fecha_inicio_vigencia,
     a.f_fecha_fin_vigencia,
     b.f_nombre,
     b.f_apellido,
     e.f_chassis,
     e.f_placa,
     e.f_registro,
     e.f_color,
     e.f_year,
     g.f_descripcion_marca,
     f.f_descripcion_modelo
FROM
     t_poliza_vehiculos     a,
     t_clientes     b,
     t_vehiculos_asegurados     d,
     t_vehiculos     e,
     t_agentes     c,
     t_marcas_vehiculos     g,
     t_modelos     f
WHERE
     a.f_codigo_cliente = b.f_codigo_cliente AND
     a.f_agente = c.f_codigo_agente AND
     a.f_wholenum = d.f_wholenum AND
     d.f_idvehiculo = e.f_keyvehiculo AND
     e.f_modelo = f.f_idmodelo AND
     f.f_idmarca = g.f_codigo_marca AND
     a.f_wholenum = 'POL000001';
This select get 20 seconds to doing. My 2 first table has 500000 reords each
one

Explain   ////////////////
Merge Join  (cost=79.44..7127.72 rows=226 width=347)
  Merge Cond: ("outer".f_wholenum = "inner".f_wholenum)
  ->  Nested Loop  (cost=0.00..7025.77 rows=1807 width=116)
        ->  Nested Loop  (cost=0.00..17.13 rows=1 width=44)
              Join Filter: ("outer".f_agente = "inner".f_codigo_agente)
              ->  Index Scan using t_poliza_vehiculos_f_wholenum_idx on
t_poliza_vehiculos a  (cost=0.00..17.07 rows=5 width=40)
                    Index Cond: (f_wholenum = 'POL000001'::bpchar)
              ->  Seq Scan on t_agentes c  (cost=0.00..0.00 rows=1 width=4)
        ->  Index Scan using f_id on t_clientes b  (cost=0.00..6986.05
rows=1807 width=72)
              Index Cond: ("outer".f_codigo_cliente = b.f_codigo_cliente)
  ->  Sort  (cost=79.44..79.76 rows=125 width=231)
        Sort Key: d.f_wholenum
        ->  Hash Join  (cost=43.53..75.09 rows=125 width=231)
              Hash Cond: ("outer".f_codigo_marca = "inner".f_idmarca)
              ->  Seq Scan on t_marcas_vehiculos g  (cost=0.00..20.00
rows=1000 width=43)
              ->  Hash  (cost=43.47..43.47 rows=25 width=188)
                    ->  Hash Join  (cost=18.15..43.47 rows=25 width=188)
                          Hash Cond: ("outer".f_idvehiculo =
"inner".f_keyvehiculo)
                          ->  Seq Scan on t_vehiculos_asegurados d
(cost=0.00..20.00 rows=1000 width=28)
                          ->  Hash  (cost=18.14..18.14 rows=5 width=160)
                                ->  Nested Loop  (cost=0.00..18.14 rows=5
width=160)
                                      ->  Seq Scan on t_vehiculos e
(cost=0.00..1.01 rows=1 width=113)
                                      ->  Index Scan using
t_modelos_f_idmodelo_idx on t_modelos f  (cost=0.00..17.07 rows=5 width=47)
                                            Index Cond: ("outer".f_modelo =
f.f_idmodelo)
/////////////////////////




*-------------------------------------------------------*
*-Edwin Quijada
*-Developer DataBase
*-JQ Microsistemas
*-809-747-2787
* " Si deseas lograr cosas excepcionales debes de hacer cosas fuera de lo
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*-------------------------------------------------------*

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