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 '1997-01-01' and o_orderdate < date '1997-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2447952.91..2447952.97 rows=25 width=34) (actual time=84749.621..84749.622 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=751325 read=736743 dirtied=55 written=1108 -> HashAggregate (cost=2447952.08..2447952.33 rows=25 width=34) (actual time=84749.535..84749.538 rows=5 loops=1) Buffers: shared hit=751322 read=736743 dirtied=55 written=1108 -> Hash Join (cost=404034.61..2447210.29 rows=74179 width=34) (actual time=14607.288..84561.802 rows=71899 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=751322 read=736743 dirtied=55 written=1108 -> Hash Join (cost=399355.61..2404700.56 rows=1854447 width=46) (actual time=14493.789..80261.526 rows=1814024 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=749140 read=736743 dirtied=55 written=1108 -> Seq Scan on lineitem (cost=0.00..1683573.65 rows=60645365 width=16) (actual time=0.017..23461.926 rows=59984826 loops=1) Buffers: shared hit=406207 read=670913 written=8 -> Hash (cost=393559.09..393559.09 rows=463722 width=38) (actual time=14493.269..14493.269 rows=453291 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 31873kB Buffers: shared hit=342933 read=65830 dirtied=55 written=1100 -> Hash Join (cost=89393.95..393559.09 rows=463722 width=38) (actual time=3519.123..14111.935 rows=453291 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=342933 read=65830 dirtied=55 written=1100 -> Bitmap Heap Scan on orders (cost=50351.73..341184.87 rows=2318609 width=8) (actual time=1520.174..5742.254 rows=2275908 loops=1) Recheck Cond: ((o_orderdate >= '1997-01-01'::date) AND (o_orderdate < '1998-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=227485 read=35128 dirtied=55 written=1100 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49772.08 rows=2318609 width=0) (actual time=1361.645..1361.645 rows=2300694 loops=1) Index Cond: ((o_orderdate >= '1997-01-01'::date) AND (o_orderdate < '1998-01-01 00:00:00'::timestamp without time zone)) Buffers: shared read=6577 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=1998.685..1998.685 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=115448 read=30702 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=21.412..1771.187 rows=299493 loops=1) Buffers: shared hit=115448 read=30702 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.057..0.182 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=0.020..0.061 rows=25 loops=1) Buffers: shared hit=2 -> Materialize (cost=0.00..1.07 rows=1 width=4) (actual time=0.002..0.002 rows=1 loops=25) Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.023..0.032 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=29.927..327.679 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=115445 read=30702 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=20.397..20.397 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=111.813..111.813 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=0.017..72.670 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 84762.308 ms (55 rows) COMMIT; COMMIT