Help improving a query. Trying to use EXPLAIN

I have a query that really isn't that complicated. Its taking close to 250ms to run, which is pretty slow. I've analyzed the query using EXPLAIN and noticed a seq scan. I have the proper indexes in place for all columns used in this query. So I'm not sure where to go from here.

Here's what I have:

cl_production=# EXPLAIN SELECT count(DISTINCT events.id) AS count_distinct_events_id FROM "events" INNER JOIN "events_tickets" ON "events_tickets".event_id = "events".id INNER JOIN "tickets" ON "tickets".id = "events_tickets".t开发者_开发百科icket_id WHERE ((events.occurs_at > '2011-08-20 07:00:00.000000') AND (tickets.company_id = 175));
                                                       QUERY PLAN                                                       
------------------------------------------------------------------------------------------------------------------------
 Aggregate  (cost=15735.79..15735.80 rows=1 width=4)
   ->  Hash Join  (cost=10540.01..15651.89 rows=33562 width=4)
         Hash Cond: (events_tickets.event_id = events.id)
         ->  Hash Join  (cost=3510.07..7516.61 rows=33562 width=4)
               Hash Cond: (events_tickets.ticket_id = tickets.id)
               ->  Seq Scan on events_tickets  (cost=0.00..1803.80 rows=124980 width=8)
               ->  Hash  (cost=3058.63..3058.63 rows=27475 width=4)
                     ->  Bitmap Heap Scan on tickets  (cost=521.19..3058.63 rows=27475 width=4)
                           Recheck Cond: (company_id = 175)
                           ->  Bitmap Index Scan on index_tickets_on_company_id  (cost=0.00..514.33 rows=27475 width=0)
                                 Index Cond: (company_id = 175)
         ->  Hash  (cost=5963.87..5963.87 rows=64965 width=4)
               ->  Index Scan using index_events_on_occurs_at on events  (cost=0.00..5963.87 rows=64965 width=4)
                     Index Cond: (occurs_at > '2011-08-20 07:00:00'::timestamp without time zone)

As stated, here are the indexes I have from my schema file:

add_index "events_tickets", ["event_id", "ticket_id"], :name => "index_events_tickets_on_event_id_and_ticket_id", :unique => true
add_index "events_tickets", ["event_id"], :name => "index_events_tickets_on_event_id"
add_index "events_tickets", ["ticket_id"], :name => "index_events_tickets_on_ticket_id"
add_index "events", ["occurs_at"], :name => "index_events_on_occurs_at"
add_index "tickets", ["company_id"], :name => "index_tickets_on_company_id"

I'm assuming the sequence scan is whats killing this query. And I have pretty thorough indexes on that table. So I'm lost. Any help would be greatly appreciated.

Thanks.

---

You should do an EXPLAIN ANALYZE to get actual timings for each node of the plan rather than just cost estimates.

Maybe this form of query, which uses a semijoin rather than count-distinct aggregation, will help:

SELECT COUNT(*)
FROM events
WHERE EXISTS (SELECT 1
              FROM events_tickets
                   JOIN tickets ON tickets.id = events_tickets.ticket_id
              WHERE tickets.company_id = 175
                    AND events_tickets.event_id = events.id)
      AND events.occurs_at > '2011-08-20 07:00:00'::timestamp