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 PLATED STEEL' ) as all_nations group by o_year order by o_year; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1742560.90..1742562.72 rows=729 width=38) (actual time=11462.146..11462.147 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=1808471 read=251847 dirtied=4 written=339 -> HashAggregate (cost=1742513.48..1742526.24 rows=729 width=38) (actual time=11462.081..11462.083 rows=2 loops=1) Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone) Buffers: shared hit=1808468 read=251847 dirtied=4 written=339 -> Hash Join (cost=39454.33..1742020.16 rows=24666 width=38) (actual time=1235.043..11419.767 rows=24941 loops=1) Hash Cond: (supplier.s_nationkey = n2.n_nationkey) Buffers: shared hit=1808468 read=251847 dirtied=4 written=339 -> Nested Loop (cost=39452.77..1741556.11 rows=24666 width=16) (actual time=1234.973..11381.300 rows=24941 loops=1) Buffers: shared hit=1808464 read=251847 dirtied=4 written=339 -> Hash Join (cost=39452.48..1733597.33 rows=24666 width=16) (actual time=1234.936..11153.734 rows=24941 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=1733541 read=251847 dirtied=4 written=339 -> Nested Loop (cost=421.79..1693857.49 rows=123332 width=20) (actual time=8.112..9831.228 rows=124704 loops=1) Buffers: shared hit=1623493 read=215747 dirtied=4 written=315 -> Nested Loop (cost=421.36..1494399.87 rows=407340 width=16) (actual time=7.880..4897.048 rows=410496 loops=1) Buffers: shared hit=291251 read=190338 dirtied=4 written=281 -> Bitmap Heap Scan on part (cost=416.64..28260.13 rows=13447 width=4) (actual time=7.757..181.076 rows=13689 loops=1) Recheck Cond: ((p_type)::text = 'ECONOMY PLATED STEEL'::text) Heap Blocks: exact=11676 Buffers: shared hit=1832 read=9929 written=19 -> Bitmap Index Scan on part_p_type_p_partkey_idx (cost=0.00..413.28 rows=13447 width=0) (actual time=5.339..5.339 rows=13689 loops=1) Index Cond: ((p_type)::text = 'ECONOMY PLATED STEEL'::text) Buffers: shared read=85 -> Bitmap Heap Scan on lineitem (cost=4.72..108.72 rows=31 width=20) (actual time=0.044..0.333 rows=30 loops=13689) Recheck Cond: (l_partkey = part.p_partkey) Heap Blocks: exact=412913 Buffers: shared hit=289419 read=180409 dirtied=4 written=262 -> Bitmap Index Scan on lineitem_l_partkey_l_quantity_l_shipmode_idx (cost=0.00..4.71 rows=31 width=0) (actual time=0.028..0.028 rows=30 loops=13689) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=40549 read=16366 written=24 -> Index Scan using orders_o_orderkey_o_orderdate_idx on orders (cost=0.43..0.48 rows=1 width=12) (actual time=0.011..0.011 rows=0 loops=410496) Index Cond: ((o_orderkey = lineitem.l_orderkey) AND (o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=1332242 read=25409 written=34 -> Hash (cost=35280.69..35280.69 rows=300000 width=4) (actual time=1222.621..1222.621 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 14626kB Buffers: shared hit=110048 read=36100 written=24 -> Nested Loop (cost=906.18..35280.69 rows=300000 width=4) (actual time=21.752..1104.681 rows=299493 loops=1) Buffers: shared hit=110048 read=36100 written=24 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.056..0.090 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=0.009..0.017 rows=25 loops=1) Buffers: shared hit=1 -> Hash (cost=1.06..1.06 rows=1 width=4) (actual time=0.022..0.022 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=0.017..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=905.11..6455.64 rows=60000 width=8) (actual time=19.640..209.244 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110046 read=36100 written=24 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.870..12.870 rows=59899 loops=5) Index Cond: (c_nationkey = n1.n_nationkey) Buffers: shared hit=7 read=825 written=1 -> Index Scan using pk_supplier on supplier (cost=0.29..0.31 rows=1 width=8) (actual time=0.008..0.008 rows=1 loops=24941) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=74923 -> Hash (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 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=0.003..0.008 rows=25 loops=1) Buffers: shared hit=1 Planning time: 8.969 ms Execution time: 11462.946 ms (70 rows) COMMIT; COMMIT