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=2427948.23..2427948.30 rows=25 width=34) (actual time=87133.557..87133.557 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=794338 read=684145 dirtied=364 written=7 -> HashAggregate (cost=2427947.40..2427947.65 rows=25 width=34) (actual time=87133.472..87133.490 rows=5 loops=1) Buffers: shared hit=794335 read=684145 dirtied=364 written=7 -> Hash Join (cost=398930.95..2427220.57 rows=72683 width=34) (actual time=16309.000..86933.813 rows=72292 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=794335 read=684145 dirtied=364 written=7 -> Hash Join (cost=394251.95..2385473.68 rows=1817053 width=46) (actual time=16171.533..82783.519 rows=1823718 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=792153 read=684145 dirtied=364 written=7 -> Seq Scan on lineitem (cost=0.00..1671922.81 rows=60225681 width=16) (actual time=0.055..22722.317 rows=60045303 loops=1) Buffers: shared hit=463764 read=605902 -> Hash (cost=388572.34..388572.34 rows=454369 width=38) (actual time=16170.921..16170.921 rows=455296 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 32013kB Buffers: shared hit=328389 read=78243 dirtied=364 written=7 -> Hash Join (cost=87150.53..388572.34 rows=454369 width=38) (actual time=4343.789..15782.982 rows=455296 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=328389 read=78243 dirtied=364 written=7 -> Bitmap Heap Scan on orders (cost=48108.32..336467.01 rows=2271846 width=8) (actual time=1902.615..6256.444 rows=2278172 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=218340 read=42142 dirtied=364 written=7 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47540.36 rows=2271846 width=0) (actual time=1783.675..1783.675 rows=2285104 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=6222 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=2440.770..2440.770 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=110049 read=36101 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=32.846..2173.298 rows=299493 loops=1) Buffers: shared hit=110049 read=36101 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.057..0.203 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=0.012..0.070 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=0.026..0.033 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=36.040..405.529 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=110046 read=36101 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=24.364..24.364 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=135.865..135.865 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=0.010..86.628 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 87147.478 ms (55 rows) COMMIT; COMMIT