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=1867590.61..1867590.67 rows=25 width=34) (actual time=13129.365..13129.366 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2508502 read=210461 dirtied=278 written=104 -> HashAggregate (cost=1867589.78..1867590.03 rows=25 width=34) (actual time=13129.295..13129.298 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2508499 read=210461 dirtied=278 written=104 -> Hash Join (cost=93062.34..1866856.68 rows=73310 width=34) (actual time=2252.974..13048.857 rows=72340 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2508499 read=210461 dirtied=278 written=104 -> Nested Loop (cost=88383.34..1847698.83 rows=1832767 width=46) (actual time=2181.370..12299.770 rows=1821879 loops=1) Buffers: shared hit=2506317 read=210461 dirtied=278 written=104 -> Hash Join (cost=88382.78..390973.01 rows=458306 width=38) (actual time=2181.341..5322.278 rows=455348 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=366220 read=41377 dirtied=58 written=14 -> Bitmap Heap Scan on orders (cost=49340.61..338754.54 rows=2291529 width=8) (actual time=991.388..3149.875 rows=2277632 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Heap Blocks: exact=255021 Buffers: shared hit=254108 read=7340 dirtied=58 written=7 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..48767.72 rows=2291529 width=0) (actual time=892.103..892.103 rows=2291364 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=1068 read=5359 written=5 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=1187.351..1187.351 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=112112 read=34037 written=7 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=22.114..1072.183 rows=299493 loops=1) Buffers: shared hit=112112 read=34037 written=7 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.045..0.121 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=0.14..12.51 rows=25 width=34) (actual time=0.011..0.037 rows=25 loops=1) Buffers: shared hit=2 -> Materialize (cost=0.00..1.07 rows=1 width=4) (actual time=0.001..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=0.015..0.020 rows=1 loops=1) Filter: (r_name = 'AFRICA'::bpchar) Rows Removed by Filter: 4 Buffers: shared hit=1 -> Bitmap Heap Scan on customer (cost=905.11..6455.64 rows=60000 width=8) (actual time=20.205..200.374 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=112109 read=34037 written=7 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.961..12.961 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 -> Index Scan using lineitem_l_orderkey_idx on lineitem (cost=0.56..3.03 rows=15 width=16) (actual time=0.012..0.014 rows=4 loops=455348) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=2140097 read=169084 dirtied=220 written=90 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=70.792..70.792 rows=100000 loops=1) Buckets: 131072 Batches: 1 Memory Usage: 4931kB Buffers: shared hit=2179 -> Seq Scan on supplier (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.020..41.776 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 7.809 ms Execution time: 13132.266 ms (56 rows) COMMIT; COMMIT