BEGIN; BEGIN EXPLAIN (ANALYZE, BUFFERS) select o_year, sum(case when nation = 'ALGERIA' then volume else 0 end) / sum(volume) as mkt_share from ( select extract(year from o_orderdate) as o_year, l_extendedprice * (1 - l_discount) as volume, n2.n_name as nation from part, supplier, lineitem, orders, customer, nation n1, nation n2, region where p_partkey = l_partkey and s_suppkey = l_suppkey and l_orderkey = o_orderkey and o_custkey = c_custkey and c_nationkey = n1.n_nationkey and n1.n_regionkey = r_regionkey and r_name = 'AFRICA' and s_nationkey = n2.n_nationkey and o_orderdate between date '1995-01-01' and date '1996-12-31' and p_type = 'ECONOMY BURNISHED TIN' ) as all_nations group by o_year order by o_year; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2138069.33..2138071.16 rows=733 width=38) (actual time=40527.528..40527.528 rows=2 loops=1) Sort Key: (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone)) Sort Method: quicksort Memory: 25kB Buffers: shared hit=642210 read=369050 dirtied=1928 written=244 -> HashAggregate (cost=2138021.62..2138034.45 rows=733 width=38) (actual time=40527.454..40527.457 rows=2 loops=1) Buffers: shared hit=642207 read=369050 dirtied=1928 written=244 -> Nested Loop (cost=498476.06..2137544.24 rows=23869 width=38) (actual time=28052.025..40443.370 rows=24574 loops=1) Buffers: shared hit=642207 read=369050 dirtied=1928 written=244 -> Nested Loop (cost=498476.06..2130736.80 rows=23869 width=16) (actual time=28051.938..40081.091 rows=24574 loops=1) Buffers: shared hit=593059 read=369050 dirtied=1928 written=244 -> Hash Join (cost=498476.06..2123786.09 rows=23869 width=16) (actual time=28051.862..39488.351 rows=24574 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=519199 read=369050 dirtied=1928 written=244 -> Nested Loop (cost=0.00..1623110.11 rows=392244 width=16) (actual time=2.888..10142.284 rows=405192 loops=1) Buffers: shared hit=257781 read=216895 dirtied=1259 written=67 -> Index Only Scan using part_p_type_p_partkey_idx on part (cost=0.00..45339.55 rows=13000 width=4) (actual time=2.753..393.924 rows=13474 loops=1) Index Cond: (p_type = 'ECONOMY BURNISHED TIN'::text) Heap Fetches: 13474 Buffers: shared hit=731 read=10773 written=3 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.00..121.06 rows=31 width=20) (actual time=0.075..0.706 rows=30 loops=13474) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=257050 read=206122 dirtied=1259 written=64 -> Hash (cost=486997.81..486997.81 rows=918260 width=8) (actual time=28047.988..28047.988 rows=911930 loops=1) Buckets: 131072 Batches: 1 Memory Usage: 35623kB Buffers: shared hit=261415 read=152155 dirtied=669 written=177 -> Hash Join (cost=136941.36..486997.81 rows=918260 width=8) (actual time=7083.471..27158.492 rows=911930 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=261415 read=152155 dirtied=669 written=177 -> Bitmap Heap Scan on orders (cost=97910.74..421567.22 rows=4591299 width=12) (actual time=4228.865..11299.054 rows=4561664 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=151368 read=116053 dirtied=669 written=58 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..96762.91 rows=4591299 width=0) (actual time=3984.767..3984.767 rows=4584480 loops=1) Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=217 read=12417 written=47 -> Hash (cost=35280.62..35280.62 rows=300000 width=4) (actual time=2853.782..2853.782 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 10530kB Buffers: shared hit=110047 read=36102 written=119 -> Nested Loop (cost=906.17..35280.62 rows=300000 width=4) (actual time=33.893..2637.835 rows=299493 loops=1) Buffers: shared hit=110047 read=36102 written=119 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.052..0.117 rows=5 loops=1) Hash Cond: (n1.n_regionkey = region.r_regionkey) Buffers: shared hit=2 -> Seq Scan on nation n1 (cost=0.00..1.25 rows=25 width=8) (actual time=0.007..0.020 rows=25 loops=1) Buffers: shared hit=1 -> Hash (cost=1.06..1.06 rows=1 width=4) (actual time=0.025..0.025 rows=1 loops=1) Buckets: 1024 Batches: 1 Memory Usage: 1kB Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.020..0.023 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=32.566..505.850 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=110045 read=36102 written=119 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=22.804..22.804 rows=59899 loops=5) Index Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=7 read=826 written=3 -> Index Scan using pk_supplier on supplier (cost=0.00..0.28 rows=1 width=8) (actual time=0.021..0.022 rows=1 loops=24574) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=73860 -> Index Scan using pk_nation on nation n2 (cost=0.00..0.27 rows=1 width=30) (actual time=0.011..0.011 rows=1 loops=24574) Index Cond: (n_nationkey = supplier.s_nationkey) Buffers: shared hit=49148 Total runtime: 40549.711 ms (64 rows) COMMIT; COMMIT