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=1879060.43..1879060.50 rows=25 width=34) (actual time=14598.705..14598.706 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2355192 read=367322 dirtied=25 written=1521 -> HashAggregate (cost=1879059.60..1879059.85 rows=25 width=34) (actual time=14598.643..14598.644 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2355189 read=367322 dirtied=25 written=1521 -> Hash Join (cost=93968.25..1878319.31 rows=74029 width=34) (actual time=2272.140..14512.093 rows=72520 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2355189 read=367322 dirtied=25 written=1521 -> Nested Loop (cost=89289.25..1859019.65 rows=1850717 width=46) (actual time=2202.681..13772.290 rows=1824898 loops=1) Buffers: shared hit=2353007 read=367322 dirtied=25 written=1521 -> Hash Join (cost=89288.68..393357.34 rows=462792 width=38) (actual time=2202.653..6041.626 rows=455810 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=299575 read=109188 dirtied=25 written=1066 -> Bitmap Heap Scan on orders (cost=50246.51..341009.90 rows=2313959 width=8) (actual time=972.637..3628.641 rows=2279304 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=256042 Buffers: shared hit=188935 read=73679 dirtied=25 written=206 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49668.02 rows=2313959 width=0) (actual time=875.501..875.501 rows=2301704 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=321 read=6251 written=30 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=1226.465..1226.465 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=110640 read=35509 written=860 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=22.783..1099.122 rows=299493 loops=1) Buffers: shared hit=110640 read=35509 written=860 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.047..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=0.013..0.039 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=0.016..0.021 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=20.043..206.655 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110637 read=35509 written=860 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=13.050..13.050 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 written=19 -> Index Scan using lineitem_l_orderkey_idx on lineitem (cost=0.56..3.02 rows=15 width=16) (actual time=0.014..0.015 rows=4 loops=455810) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=2053432 read=258134 written=455 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=68.695..68.695 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=0.010..40.244 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 7.282 ms Execution time: 14601.195 ms (56 rows) COMMIT; COMMIT