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 = 'PROMO POLISHED BRASS' ) as all_nations group by o_year order by o_year; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2203648.78..2203650.61 rows=731 width=38) (actual time=30455.829..30455.830 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=796901 read=223269 dirtied=2879 written=899 -> HashAggregate (cost=2203601.22..2203614.01 rows=731 width=38) (actual time=30455.738..30455.739 rows=2 loops=1) Buffers: shared hit=796898 read=223269 dirtied=2879 written=899 -> Nested Loop (cost=501225.53..2203102.24 rows=24949 width=38) (actual time=21887.031..30384.854 rows=24956 loops=1) Buffers: shared hit=796898 read=223269 dirtied=2879 written=899 -> Nested Loop (cost=501225.53..2195986.78 rows=24949 width=16) (actual time=21886.942..30180.965 rows=24956 loops=1) Buffers: shared hit=746986 read=223269 dirtied=2879 written=899 -> Hash Join (cost=501225.53..2188721.58 rows=24949 width=16) (actual time=21886.891..29811.082 rows=24956 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=671963 read=223269 dirtied=2879 written=899 -> Nested Loop (cost=0.00..1685192.82 rows=410747 width=16) (actual time=0.455..6747.604 rows=409098 loops=1) Buffers: shared hit=273798 read=206602 dirtied=2626 written=118 -> Index Only Scan using part_p_type_p_partkey_idx on part (cost=0.00..47057.51 rows=13573 width=4) (actual time=0.372..146.295 rows=13596 loops=1) Index Cond: (p_type = 'PROMO POLISHED BRASS'::text) Heap Fetches: 13596 Buffers: shared hit=8360 read=3316 written=3 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.00..120.38 rows=31 width=20) (actual time=0.047..0.470 rows=30 loops=13596) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=265438 read=203286 dirtied=2626 written=115 -> Hash (cost=489734.12..489734.12 rows=919313 width=8) (actual time=21885.337..21885.337 rows=911872 loops=1) Buckets: 131072 Batches: 1 Memory Usage: 35620kB Buffers: shared hit=398162 read=16667 dirtied=253 written=781 -> Hash Join (cost=138807.40..489734.12 rows=919313 width=8) (actual time=4901.371..21000.722 rows=911872 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=398162 read=16667 dirtied=253 written=781 -> Bitmap Heap Scan on orders (cost=99776.78..424273.25 rows=4596565 width=12) (actual time=3402.555..8122.701 rows=4561632 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=255804 read=12876 dirtied=253 written=326 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..98627.63 rows=4596565 width=0) (actual time=3284.725..3284.725 rows=4598186 loops=1) Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=762 read=12370 written=326 -> Hash (cost=35280.62..35280.62 rows=300000 width=4) (actual time=1498.444..1498.444 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 10530kB Buffers: shared hit=142358 read=3791 written=455 -> Nested Loop (cost=906.17..35280.62 rows=300000 width=4) (actual time=47.304..1328.832 rows=299493 loops=1) Buffers: shared hit=142358 read=3791 written=455 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.041..0.097 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=0.006..0.020 rows=25 loops=1) Buffers: shared hit=1 -> Hash (cost=1.06..1.06 rows=1 width=4) (actual time=0.020..0.020 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=0.017..0.019 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=34.800..245.114 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=142356 read=3791 written=455 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=25.237..25.237 rows=59899 loops=5) Index Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=7 read=826 written=197 -> Index Scan using pk_supplier on supplier (cost=0.00..0.28 rows=1 width=8) (actual time=0.012..0.013 rows=1 loops=24956) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=75023 -> Index Scan using pk_nation on nation n2 (cost=0.00..0.27 rows=1 width=30) (actual time=0.005..0.005 rows=1 loops=24956) Index Cond: (n_nationkey = supplier.s_nationkey) Buffers: shared hit=49912 Total runtime: 30470.923 ms (64 rows) COMMIT; COMMIT