BEGIN; BEGIN EXPLAIN (ANALYZE, BUFFERS) select o_year, sum(case when nation = 'MOZAMBIQUE' 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 = 'MEDIUM POLISHED STEEL' ) as all_nations group by o_year order by o_year; QUERY PLAN ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1719388.05..1719389.87 rows=729 width=38) (actual time=10754.275..10754.276 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=2028016 read=247751 dirtied=658 written=253 -> HashAggregate (cost=1719340.63..1719353.39 rows=729 width=38) (actual time=10754.210..10754.211 rows=2 loops=1) Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone) Buffers: shared hit=2028013 read=247751 dirtied=658 written=253 -> Hash Join (cost=39444.48..1718858.45 rows=24109 width=38) (actual time=807.650..10716.294 rows=24034 loops=1) Hash Cond: (supplier.s_nationkey = n2.n_nationkey) Buffers: shared hit=2028013 read=247751 dirtied=658 written=253 -> Nested Loop (cost=39442.91..1718404.84 rows=24109 width=16) (actual time=807.596..10683.852 rows=24034 loops=1) Buffers: shared hit=2028009 read=247751 dirtied=658 written=253 -> Hash Join (cost=39442.62..1710625.76 rows=24109 width=16) (actual time=807.577..10497.478 rows=24034 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=1955763 read=247751 dirtied=658 written=253 -> Nested Loop (cost=411.94..1670901.93 rows=120546 width=20) (actual time=7.427..9617.243 rows=120849 loops=1) Buffers: shared hit=1810493 read=246873 dirtied=658 written=252 -> Nested Loop (cost=411.50..1475876.91 rows=398301 width=16) (actual time=7.341..4022.086 rows=397496 loops=1) Buffers: shared hit=280666 read=184575 dirtied=477 written=159 -> Bitmap Heap Scan on part (cost=410.94..27991.24 rows=13227 width=4) (actual time=7.251..159.064 rows=13278 loops=1) Recheck Cond: ((p_type)::text = 'MEDIUM POLISHED STEEL'::text) Heap Blocks: exact=11367 Buffers: shared hit=3433 read=8017 written=5 -> Bitmap Index Scan on part_p_type_p_partkey_idx (cost=0.00..407.63 rows=13227 width=0) (actual time=5.014..5.014 rows=13278 loops=1) Index Cond: ((p_type)::text = 'MEDIUM POLISHED STEEL'::text) Buffers: shared hit=1 read=82 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.56..109.15 rows=31 width=20) (actual time=0.027..0.281 rows=30 loops=13278) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=277233 read=176558 dirtied=477 written=154 -> Index Scan using pk_orders on orders (cost=0.43..0.48 rows=1 width=12) (actual time=0.013..0.014 rows=0 loops=397496) 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=1529827 read=62298 dirtied=181 written=93 -> Hash (cost=35280.69..35280.69 rows=300000 width=4) (actual time=795.276..795.276 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 14626kB Buffers: shared hit=145270 read=878 written=1 -> Nested Loop (cost=906.18..35280.69 rows=300000 width=4) (actual time=19.556..702.319 rows=299493 loops=1) Buffers: shared hit=145270 read=878 written=1 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.049..0.083 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..0.013 rows=25 loops=1) Buffers: shared hit=1 -> Hash (cost=1.06..1.06 rows=1 width=4) (actual time=0.016..0.016 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..0.012 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=17.392..130.619 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=145268 read=878 written=1 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=11.465..11.465 rows=59899 loops=5) Index Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=12 read=820 written=1 -> Index Scan using pk_supplier on supplier (cost=0.29..0.31 rows=1 width=8) (actual time=0.006..0.007 rows=1 loops=24034) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=72246 -> Hash (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 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=0.005..0.007 rows=25 loops=1) Buffers: shared hit=1 Planning time: 7.192 ms Execution time: 10755.161 ms (68 rows) COMMIT; COMMIT