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=2431346.88..2431346.94 rows=25 width=34) (actual time=71999.099..71999.099 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=546431 read=933395 dirtied=253 written=7 -> HashAggregate (cost=2431346.05..2431346.30 rows=25 width=34) (actual time=71998.979..71998.982 rows=5 loops=1) Buffers: shared hit=546428 read=933395 dirtied=253 written=7 -> Hash Join (cost=399959.31..2430614.94 rows=73111 width=34) (actual time=13265.001..71843.774 rows=72300 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=546428 read=933395 dirtied=253 written=7 -> Hash Join (cost=395280.31..2388600.75 rows=1830204 width=46) (actual time=13131.168..68276.170 rows=1823740 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=544246 read=933395 dirtied=253 written=7 -> Seq Scan on lineitem (cost=0.00..1673592.26 rows=60285226 width=16) (actual time=0.028..17327.489 rows=60046221 loops=1) Buffers: shared hit=212802 read=857938 written=7 -> Hash (cost=389559.54..389559.54 rows=457661 width=38) (actual time=13130.355..13130.355 rows=455295 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32013kB Buffers: shared hit=331444 read=75457 dirtied=253 -> Hash Join (cost=87543.23..389559.54 rows=457661 width=38) (actual time=3257.783..12781.973 rows=455295 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=331444 read=75457 dirtied=253 -> Bitmap Heap Scan on orders (cost=48501.02..337359.58 rows=2288304 width=8) (actual time=1406.845..5144.645 rows=2278174 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=221396 read=39355 dirtied=253 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47928.94 rows=2288304 width=0) (actual time=1310.398..1310.398 rows=2287382 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 read=6238 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=1850.549..1850.549 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=110048 read=36102 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=33.656..1635.924 rows=299493 loops=1) Buffers: shared hit=110048 read=36102 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.069..0.193 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..0.057 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=0.038..0.046 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=31.738..304.534 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=110045 read=36102 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=22.116..22.116 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=131.660..131.660 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..83.316 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 72010.816 ms (55 rows) COMMIT; COMMIT