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=2448246.07..2448246.13 rows=25 width=34) (actual time=80650.847..80650.847 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=1121331 read=368060 written=115 -> HashAggregate (cost=2448245.24..2448245.49 rows=25 width=34) (actual time=80650.754..80650.758 rows=5 loops=1) Buffers: shared hit=1121328 read=368060 written=115 -> Hash Join (cost=403049.52..2447513.21 rows=73203 width=34) (actual time=13013.716..80477.420 rows=72344 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=1121328 read=368060 written=115 -> Hash Join (cost=398370.52..2405452.08 rows=1832505 width=46) (actual time=12877.212..76091.313 rows=1821926 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=1119146 read=368060 written=115 -> Seq Scan on lineitem (cost=0.00..1685233.66 rows=60704566 width=16) (actual time=0.037..19526.596 rows=60044994 loops=1) Buffers: shared hit=720204 read=357984 written=99 -> Hash (cost=392642.50..392642.50 rows=458241 width=38) (actual time=12876.578..12876.578 rows=455345 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32017kB Buffers: shared hit=398942 read=10076 written=16 -> Hash Join (cost=88793.04..392642.50 rows=458241 width=38) (actual time=2755.812..12525.473 rows=455345 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=398942 read=10076 written=16 -> Bitmap Heap Scan on orders (cost=49750.82..340425.87 rows=2291203 width=8) (actual time=1437.150..4867.662 rows=2277498 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=254215 read=8653 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49178.02 rows=2291203 width=0) (actual time=1265.903..1265.903 rows=2302785 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 hit=266 read=6315 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=1317.083..1317.083 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=144727 read=1423 written=16 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=38.917..1109.367 rows=299493 loops=1) Buffers: shared hit=144727 read=1423 written=16 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.048..0.167 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=0.008..0.041 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=0.025..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=32.111..199.318 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=144724 read=1423 written=16 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=21.537..21.537 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=8 read=825 written=6 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=135.775..135.775 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=0.014..89.204 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 80677.357 ms (55 rows) COMMIT; COMMIT