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 = 'SMALL BRUSHED STEEL' ) as all_nations group by o_year order by o_year; QUERY PLAN ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1769490.38..1769492.20 rows=729 width=38) (actual time=12114.913..12114.914 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=1945617 read=337603 dirtied=1726 written=312 -> HashAggregate (cost=1769442.96..1769455.72 rows=729 width=38) (actual time=12114.844..12114.844 rows=2 loops=1) Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone) Buffers: shared hit=1945614 read=337603 dirtied=1726 written=312 -> Hash Join (cost=39455.89..1768942.26 rows=25035 width=38) (actual time=1163.644..12074.006 rows=24062 loops=1) Hash Cond: (supplier.s_nationkey = n2.n_nationkey) Buffers: shared hit=1945614 read=337603 dirtied=1726 written=312 -> Nested Loop (cost=39454.32..1768471.29 rows=25035 width=16) (actual time=1163.582..12037.461 rows=24062 loops=1) Buffers: shared hit=1945610 read=337603 dirtied=1726 written=312 -> Hash Join (cost=39454.03..1760393.44 rows=25035 width=16) (actual time=1163.561..11843.187 rows=24062 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=1873274 read=337603 dirtied=1726 written=312 -> Nested Loop (cost=423.35..1720643.00 rows=125175 width=20) (actual time=7.503..10611.685 rows=121087 loops=1) Buffers: shared hit=1763227 read=301502 dirtied=1726 written=312 -> Nested Loop (cost=422.91..1518124.16 rows=413594 width=16) (actual time=7.033..4410.665 rows=398753 loops=1) Buffers: shared hit=251416 read=216150 dirtied=1665 written=220 -> Bitmap Heap Scan on part (cost=422.35..28524.71 rows=13667 width=4) (actual time=6.970..133.576 rows=13244 loops=1) Recheck Cond: ((p_type)::text = 'SMALL BRUSHED STEEL'::text) Heap Blocks: exact=11341 Buffers: shared hit=5503 read=5906 written=4 -> Bitmap Index Scan on part_p_type_p_partkey_idx (cost=0.00..418.93 rows=13667 width=0) (actual time=4.738..4.738 rows=13244 loops=1) Index Cond: ((p_type)::text = 'SMALL BRUSHED STEEL'::text) Buffers: shared read=68 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.56..108.68 rows=31 width=20) (actual time=0.029..0.313 rows=30 loops=13244) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=245913 read=210244 dirtied=1665 written=216 -> Index Scan using pk_orders on orders (cost=0.43..0.48 rows=1 width=12) (actual time=0.015..0.015 rows=0 loops=398753) Index Cond: (o_orderkey = lineitem.l_orderkey) Filter: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Rows Removed by Filter: 1 Buffers: shared hit=1511811 read=85352 dirtied=61 written=92 -> Hash (cost=35280.69..35280.69 rows=300000 width=4) (actual time=1151.703..1151.703 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 14626kB Buffers: shared hit=110047 read=36101 -> Nested Loop (cost=906.18..35280.69 rows=300000 width=4) (actual time=21.294..1061.806 rows=299493 loops=1) Buffers: shared hit=110047 read=36101 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.044..0.073 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..0.015 rows=25 loops=1) Buffers: shared hit=1 -> Hash (cost=1.06..1.06 rows=1 width=4) (actual time=0.017..0.017 rows=1 loops=1) Buckets: 1024 Batches: 1 Memory Usage: 9kB Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.010..0.011 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=18.761..201.304 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110045 read=36101 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.341..12.341 rows=59899 loops=5) Index Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=7 read=825 -> Index Scan using pk_supplier on supplier (cost=0.29..0.31 rows=1 width=8) (actual time=0.007..0.007 rows=1 loops=24062) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=72336 -> Hash (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 rows=25 loops=1) Buckets: 1024 Batches: 1 Memory Usage: 10kB Buffers: shared hit=1 -> Seq Scan on nation n2 (cost=0.00..1.25 rows=25 width=30) (actual time=0.004..0.009 rows=25 loops=1) Buffers: shared hit=1 Planning time: 8.698 ms Execution time: 12115.891 ms (68 rows) COMMIT; COMMIT