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 '1993-01-01' and o_orderdate < date '1993-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1883620.80..1883620.86 rows=25 width=34) (actual time=14502.647..14502.648 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2288828 read=434894 dirtied=339 written=288 -> HashAggregate (cost=1883619.97..1883620.22 rows=25 width=34) (actual time=14502.584..14502.587 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2288825 read=434894 dirtied=339 written=288 -> Hash Join (cost=94013.06..1882879.05 rows=74092 width=34) (actual time=2355.840..14420.423 rows=72542 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2288825 read=434894 dirtied=339 written=288 -> Nested Loop (cost=89334.06..1863566.47 rows=1852355 width=46) (actual time=2290.275..13689.858 rows=1825251 loops=1) Buffers: shared hit=2286643 read=434894 dirtied=339 written=288 -> Hash Join (cost=89333.49..394203.27 rows=463198 width=38) (actual time=2290.194..6585.946 rows=455891 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=217464 read=192081 dirtied=193 written=285 -> Bitmap Heap Scan on orders (cost=50291.32..341844.16 rows=2315989 width=8) (actual time=1176.524..4280.880 rows=2279376 loops=1) Recheck Cond: ((o_orderdate >= '1993-01-01'::date) AND (o_orderdate < '1994-01-01 00:00:00'::timestamp without time zone)) Heap Blocks: exact=256801 Buffers: shared hit=107416 read=155980 dirtied=193 written=87 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49712.32 rows=2315989 width=0) (actual time=1058.945..1058.945 rows=2308446 loops=1) Index Cond: ((o_orderdate >= '1993-01-01'::date) AND (o_orderdate < '1994-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=62 read=6533 written=83 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=1109.810..1109.810 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=110048 read=36101 written=198 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=20.005..982.958 rows=299493 loops=1) Buffers: shared hit=110048 read=36101 written=198 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.040..0.119 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..0.032 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=0.014..0.026 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=17.888..183.740 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110045 read=36101 written=198 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=11.674..11.674 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 written=5 -> Index Scan using pk_lineitem on lineitem (cost=0.56..3.02 rows=15 width=16) (actual time=0.012..0.014 rows=4 loops=455891) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=2069179 read=242813 dirtied=146 written=3 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=64.846..64.846 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=0.011..38.413 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 6.982 ms Execution time: 14504.303 ms (56 rows) COMMIT; COMMIT