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 '1994-01-01' and o_orderdate < date '1994-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2423499.97..2423500.03 rows=25 width=34) (actual time=86268.152..86268.153 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=889747 read=586110 dirtied=253 written=510 -> HashAggregate (cost=2423499.14..2423499.39 rows=25 width=34) (actual time=86268.058..86268.062 rows=5 loops=1) Buffers: shared hit=889744 read=586110 dirtied=253 written=510 -> Hash Join (cost=398428.63..2422772.67 rows=72647 width=34) (actual time=17414.353..86107.387 rows=72312 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=889744 read=586110 dirtied=253 written=510 -> Hash Join (cost=393749.63..2381043.54 rows=1816183 width=46) (actual time=17297.652..82246.888 rows=1823940 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=887562 read=586110 dirtied=253 written=510 -> Seq Scan on lineitem (cost=0.00..1668603.40 rows=60105740 width=16) (actual time=0.038..20979.697 rows=60045603 loops=1) Buffers: shared hit=765819 read=301727 -> Hash (cost=388072.73..388072.73 rows=454152 width=38) (actual time=17296.794..17296.794 rows=455330 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32016kB Buffers: shared hit=121743 read=284383 dirtied=253 written=510 -> Hash Join (cost=87179.42..388072.73 rows=454152 width=38) (actual time=3495.721..16034.712 rows=455330 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=121743 read=284383 dirtied=253 written=510 -> Bitmap Heap Scan on orders (cost=48137.21..335973.64 rows=2270762 width=8) (actual time=1806.702..7321.266 rows=2278204 loops=1) Recheck Cond: ((o_orderdate >= '1994-01-01'::date) AND (o_orderdate < '1995-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=5738 read=254238 dirtied=253 written=510 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47569.52 rows=2270762 width=0) (actual time=1647.283..1647.283 rows=2280522 loops=1) Index Cond: ((o_orderdate >= '1994-01-01'::date) AND (o_orderdate < '1995-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=341 read=5881 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=1688.176..1688.176 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=116005 read=30145 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=31.329..1151.744 rows=299493 loops=1) Buffers: shared hit=116005 read=30145 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.059..0.329 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=0.015..0.206 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=0.027..0.037 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=24.973..214.737 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=116002 read=30145 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=16.633..16.633 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=116.501..116.501 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..72.575 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 86297.988 ms (55 rows) COMMIT; COMMIT