Administración de PostgreSQL
EXPLAIN - otro ejemplo

alvh=# EXPLAIN SELECT * FROM multi NATURAL JOIN primario LIMIT 20;
NOTICE:  QUERY PLAN:

Limit  (cost=0.00..40.87 rows=20 width=30)
  ->  Nested Loop  (cost=0.00..30651.00 rows=15000
                    width=30)
        ->  Seq Scan on multi  (cost=0.00..261.00
                                rows=15000 width=22)
        ->  Index Scan using primario_pkey on
            primario  (cost=0.00..2.01 rows=1 width=8)

EXPLAIN