BEGIN; BEGIN EXPLAIN (ANALYZE, BUFFERS) select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AFRICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2426739.59..2426739.65 rows=25 width=34) (actual time=85301.165..85301.165 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=1093556 read=383616 dirtied=1 written=1 -> HashAggregate (cost=2426738.76..2426739.01 rows=25 width=34) (actual time=85301.080..85301.083 rows=5 loops=1) Buffers: shared hit=1093553 read=383616 dirtied=1 written=1 -> Hash Join (cost=399333.23..2426007.40 rows=73136 width=34) (actual time=14040.778..85088.571 rows=72287 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=1093553 read=383616 dirtied=1 written=1 -> Hash Join (cost=394654.23..2384029.18 rows=1828393 width=46) (actual time=13924.249..80636.217 rows=1821911 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=1091371 read=383616 dirtied=1 written=1 -> Seq Scan on lineitem (cost=0.00..1670263.34 rows=60165534 width=16) (actual time=0.056..22359.552 rows=60045379 loops=1) Buffers: shared hit=697992 read=370616 dirtied=1 written=1 -> Hash (cost=388939.14..388939.14 rows=457207 width=38) (actual time=13923.683..13923.683 rows=455385 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32020kB Buffers: shared hit=393379 read=13000 -> Hash Join (cost=87475.95..388939.14 rows=457207 width=38) (actual time=3172.433..13379.826 rows=455385 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=393379 read=13000 -> Bitmap Heap Scan on orders (cost=48433.73..336752.23 rows=2286033 width=8) (actual time=1803.510..5334.132 rows=2277879 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=248073 read=12156 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47862.23 rows=2286033 width=0) (actual time=1644.333..1644.333 rows=2282432 loops=1) Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared read=6221 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=1367.276..1367.276 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=145306 read=844 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=31.294..1171.488 rows=299493 loops=1) Buffers: shared hit=145306 read=844 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.053..0.161 rows=5 loops=1) Join Filter: (nation.n_regionkey = region.r_regionkey) Rows Removed by Join Filter: 20 Buffers: shared hit=3 -> Index Scan using pk_nation on nation (cost=0.00..12.63 rows=25 width=34) (actual time=0.010..0.042 rows=25 loops=1) Buffers: shared hit=2 -> Materialize (cost=0.00..1.07 rows=1 width=4) (actual time=0.002..0.003 rows=1 loops=25) Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.024..0.030 rows=1 loops=1) Filter: (r_name = 'AFRICA'::bpchar) Rows Removed by Filter: 4 Buffers: shared hit=1 -> Bitmap Heap Scan on customer (cost=905.09..6455.63 rows=60000 width=8) (actual time=29.726..212.688 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=145303 read=844 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=20.315..20.315 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=826 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=115.537..115.537 rows=100000 loops=1) Buckets: 16384 Batches: 1 Memory Usage: 3907kB Buffers: shared hit=2179 -> Seq Scan on supplier (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.010..74.361 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 85338.806 ms (55 rows) COMMIT; COMMIT