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 '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2436062.56..2436062.63 rows=25 width=34) (actual time=89162.846..89162.847 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=1068951 read=412910 written=3275 -> HashAggregate (cost=2436061.73..2436061.98 rows=25 width=34) (actual time=89162.730..89162.753 rows=5 loops=1) Buffers: shared hit=1068948 read=412910 written=3275 -> Hash Join (cost=401170.31..2435324.49 rows=73724 width=34) (actual time=15346.152..88957.347 rows=72258 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=1068948 read=412910 written=3275 -> Hash Join (cost=396491.31..2393046.85 rows=1843070 width=46) (actual time=15205.973..84482.270 rows=1820174 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=1066766 read=412910 written=3275 -> Seq Scan on lineitem (cost=0.00..1676223.56 rows=60380256 width=16) (actual time=0.024..23763.182 rows=59985687 loops=1) Buffers: shared hit=711730 read=360691 -> Hash (cost=390733.69..390733.69 rows=460610 width=38) (actual time=15205.187..15205.187 rows=454928 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 31988kB Buffers: shared hit=355036 read=52219 written=3275 -> Hash Join (cost=88158.40..390733.69 rows=460610 width=38) (actual time=4606.195..14850.820 rows=454928 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=355036 read=52219 written=3275 -> Bitmap Heap Scan on orders (cost=49116.18..338448.93 rows=2303050 width=8) (actual time=2041.328..5893.722 rows=2275403 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=244982 read=16123 written=1238 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..48540.42 rows=2303050 width=0) (actual time=1909.013..1909.013 rows=2289416 loops=1) Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=125 read=6213 written=370 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=2564.603..2564.603 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=110054 read=36096 written=2037 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=38.019..2313.242 rows=299493 loops=1) Buffers: shared hit=110054 read=36096 written=2037 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.051..0.181 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=0.011..0.051 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=0.025..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=34.746..435.510 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=110051 read=36096 written=2037 -> 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 written=70 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=139.582..139.582 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=0.019..91.197 rows=100000 loops=1) Buffers: shared hit=2179 Total runtime: 89181.819 ms (55 rows) COMMIT; COMMIT