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=1865308.45..1865308.51 rows=25 width=34) (actual time=12793.289..12793.290 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2226286 read=483735 dirtied=368 written=930 -> HashAggregate (cost=1865307.62..1865307.87 rows=25 width=34) (actual time=12793.222..12793.222 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2226283 read=483735 dirtied=368 written=930 -> Hash Join (cost=92389.86..1864573.04 rows=73458 width=34) (actual time=1877.262..12716.370 rows=71916 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2226283 read=483735 dirtied=368 written=930 -> Nested Loop (cost=87710.86..1845385.61 rows=1836513 width=46) (actual time=1807.250..12016.869 rows=1815851 loops=1) Buffers: shared hit=2224101 read=483735 dirtied=368 written=930 -> Hash Join (cost=87710.30..389889.72 rows=459233 width=38) (actual time=1807.217..5187.767 rows=453776 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=285374 read=121531 dirtied=127 written=456 -> Bitmap Heap Scan on orders (cost=48668.13..337644.60 rows=2296165 width=8) (actual time=814.208..3104.016 rows=2277990 loops=1) Recheck Cond: ((o_orderdate >= '1997-01-01'::date) AND (o_orderdate < '1998-01-01 00:00:00'::timestamp without time zone)) Heap Blocks: exact=254516 Buffers: shared hit=175225 read=85531 dirtied=127 written=139 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..48094.08 rows=2296165 width=0) (actual time=728.575..728.575 rows=2287055 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 hit=264 read=5976 written=28 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=989.705..989.705 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=110149 read=36000 written=317 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=18.192..871.847 rows=299493 loops=1) Buffers: shared hit=110149 read=36000 written=317 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.039..0.110 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=0.009..0.033 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=0.012..0.017 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=16.828..161.552 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110146 read=36000 written=317 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=10.922..10.922 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 written=5 -> Index Scan using lineitem_l_orderkey_idx on lineitem (cost=0.56..3.02 rows=15 width=16) (actual time=0.012..0.014 rows=4 loops=453776) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=1938727 read=362204 dirtied=241 written=474 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=69.284..69.284 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=0.006..44.258 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 6.620 ms Execution time: 12795.873 ms (56 rows) COMMIT; COMMIT