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=2455879.03..2455879.09 rows=25 width=34) (actual time=91622.224..91622.225 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=967630 read=525738 dirtied=1069 written=888 -> HashAggregate (cost=2455878.20..2455878.45 rows=25 width=34) (actual time=91622.111..91622.137 rows=5 loops=1) Buffers: shared hit=967627 read=525738 dirtied=1069 written=888 -> Hash Join (cost=404440.47..2455140.94 rows=73726 width=34) (actual time=25347.484..91456.527 rows=72347 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=967627 read=525738 dirtied=1069 written=888 -> Hash Join (cost=399761.47..2412850.90 rows=1843689 width=46) (actual time=25180.354..87413.905 rows=1822103 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=965445 read=525738 dirtied=1069 written=888 -> Seq Scan on lineitem (cost=0.00..1690229.04 rows=60884704 width=16) (actual time=0.030..20649.264 rows=60044793 loops=1) Buffers: shared hit=631042 read=450340 dirtied=1069 written=888 -> Hash (cost=393998.54..393998.54 rows=461034 width=38) (actual time=25179.645..25179.645 rows=455338 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32016kB Buffers: shared hit=334403 read=75398 -> Hash Join (cost=89100.23..393998.54 rows=461034 width=38) (actual time=8238.119..24748.088 rows=455338 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=334403 read=75398 -> Bitmap Heap Scan on orders (cost=50058.01..341701.59 rows=2305172 width=8) (actual time=2455.472..11507.056 rows=2277530 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=224355 read=39296 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49481.72 rows=2305172 width=0) (actual time=2311.401..2311.401 rows=2309697 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=6605 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=5782.320..5782.320 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=110048 read=36102 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=53.384..5505.773 rows=299493 loops=1) Buffers: shared hit=110048 read=36102 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.053..0.202 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..0.072 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=0.026..0.033 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=44.198..1074.875 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=110045 read=36102 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=34.504..34.504 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=165.108..165.108 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=0.013..117.056 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 91637.299 ms (55 rows) COMMIT; COMMIT