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=1860067.55..1860067.61 rows=25 width=34) (actual time=14392.901..14392.903 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2361104 read=356237 dirtied=200 written=4991 -> HashAggregate (cost=1860066.72..1860066.97 rows=25 width=34) (actual time=14392.834..14392.835 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2361101 read=356237 dirtied=200 written=4991 -> Hash Join (cost=92091.10..1859335.79 rows=73093 width=34) (actual time=2514.275..14308.284 rows=72438 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2361101 read=356237 dirtied=200 written=4991 -> Nested Loop (cost=87412.10..1840221.29 rows=1827276 width=46) (actual time=2453.994..13600.625 rows=1822505 loops=1) Buffers: shared hit=2358919 read=356237 dirtied=200 written=4991 -> Hash Join (cost=87411.54..388812.17 rows=456604 width=38) (actual time=2453.960..6470.524 rows=455258 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=275642 read=130747 dirtied=200 written=3786 -> Bitmap Heap Scan on orders (cost=48369.37..336642.64 rows=2283018 width=8) (actual time=1263.752..4110.284 rows=2276798 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=254016 Buffers: shared hit=165594 read=94646 dirtied=200 written=1443 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47798.61 rows=2283018 width=0) (actual time=1146.320..1146.320 rows=2283990 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=120 read=6104 written=399 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=1186.573..1186.573 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=110048 read=36101 written=2343 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=19.481..1058.759 rows=299493 loops=1) Buffers: shared hit=110048 read=36101 written=2343 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.047..0.128 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=0.018..0.051 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..0.018 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=18.501..198.699 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110045 read=36101 written=2343 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.150..12.150 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 written=37 -> Index Scan using pk_lineitem on lineitem (cost=0.56..3.03 rows=15 width=16) (actual time=0.012..0.014 rows=4 loops=455258) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=2083277 read=225490 written=1205 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=59.610..59.610 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..35.811 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 6.150 ms Execution time: 14394.835 ms (56 rows) COMMIT; COMMIT