table partition

gistfile1.txt

SET constraint_exclusion = on;
EXPLAIN (ANALYZE ON, BUFFERS ON) select * from daily_keyphrase_views_main WHERE writer_id = '585144' AND date BETWEEN '2011-01-01' AND '2011-01-31' AND partition_id = (585144 % 41);


Result  (cost=0.00..16912.91 rows=220703 width=71) (actual time=857.574..4492.705 rows=218272 loops=1)
  Buffers: shared read=3275
  ->  Append  (cost=0.00..16912.91 rows=220703 width=71) (actual time=857.572..4405.989 rows=218272 loops=1)
        Buffers: shared read=3275
        ->  Seq Scan on daily_keyphrase_views_main  (cost=0.00..12.60 rows=1 width=556) (actual time=0.001..0.001 rows=0 loops=1)
              Filter: ((date >= '2011-01-01'::date) AND (date <= '2011-01-31'::date) AND (writer_id = 585144) AND (partition_id = 33))
        ->  Bitmap Heap Scan on daily_keyphrase_views_p33 daily_keyphrase_views_main  (cost=5242.27..16900.31 rows=220702 width=71) (actual time=857.569..4353.713 rows=218272 loops=1)
              Recheck Cond: ((writer_id = 585144) AND (date >= '2011-01-01'::date) AND (date <= '2011-01-31'::date))
              Filter: (partition_id = 33)
              Buffers: shared read=3275
              ->  Bitmap Index Scan on index_daily_keyphrase_views_p33_on_writer_id_n_date  (cost=0.00..5187.09 rows=220702 width=0) (actual time=822.326..822.326 rows=218272 loops=1)
                    Index Cond: ((writer_id = 585144) AND (date >= '2011-01-01'::date) AND (date <= '2011-01-31'::date))
                    Buffers: shared read=600
Total runtime: 4522.369 ms