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 = 'LARGE POLISHED STEEL' ) as all_nations group by o_year order by o_year; QUERY PLAN ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1740394.69..1740396.51 rows=730 width=38) (actual time=10392.007..10392.008 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=1875095 read=417190 dirtied=3397 written=181 -> HashAggregate (cost=1740347.19..1740359.97 rows=730 width=38) (actual time=10391.951..10391.953 rows=2 loops=1) Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone) Buffers: shared hit=1875092 read=417190 dirtied=3397 written=181 -> Hash Join (cost=39449.66..1739854.51 rows=24634 width=38) (actual time=1003.597..10355.117 rows=24416 loops=1) Hash Cond: (supplier.s_nationkey = n2.n_nationkey) Buffers: shared hit=1875092 read=417190 dirtied=3397 written=181 -> Nested Loop (cost=39448.10..1739391.06 rows=24634 width=16) (actual time=1003.530..10324.701 rows=24416 loops=1) Buffers: shared hit=1875088 read=417190 dirtied=3397 written=181 -> Hash Join (cost=39447.81..1731434.56 rows=24659 width=16) (actual time=1003.489..10140.687 rows=24416 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=1804309 read=414585 dirtied=3397 written=179 -> Nested Loop (cost=417.12..1691694.92 rows=123295 width=20) (actual time=7.021..9077.561 rows=121182 loops=1) Buffers: shared hit=1694262 read=378484 dirtied=3397 written=179 -> Nested Loop (cost=416.69..1492440.13 rows=406917 width=16) (actual time=6.669..3503.764 rows=400067 loops=1) Buffers: shared hit=259884 read=210390 dirtied=3262 written=73 -> Bitmap Heap Scan on part (cost=416.12..28180.29 rows=13380 width=4) (actual time=6.599..154.443 rows=13309 loops=1) Recheck Cond: ((p_type)::text = 'LARGE POLISHED STEEL'::text) Heap Blocks: exact=11377 Buffers: shared hit=1 read=11459 written=4 -> Bitmap Index Scan on part_p_type_p_partkey_idx (cost=0.00..412.78 rows=13380 width=0) (actual time=4.505..4.505 rows=13309 loops=1) Index Cond: ((p_type)::text = 'LARGE POLISHED STEEL'::text) Buffers: shared read=83 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.56..109.13 rows=31 width=20) (actual time=0.023..0.242 rows=30 loops=13309) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=259883 read=198931 dirtied=3262 written=69 -> Index Scan using pk_orders on orders (cost=0.43..0.48 rows=1 width=12) (actual time=0.013..0.013 rows=0 loops=400067) 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=1434378 read=168094 dirtied=135 written=106 -> Hash (cost=35280.69..35280.69 rows=300000 width=4) (actual time=993.456..993.456 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=19.108..908.675 rows=299493 loops=1) Buffers: shared hit=110047 read=36101 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.042..0.099 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=0.008..0.025 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=0.009..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=16.639..171.601 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=10.897..10.897 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=0.006..0.007 rows=1 loops=24416) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=70779 read=2605 written=2 -> Hash (cost=1.25..1.25 rows=25 width=30) (actual time=0.025..0.025 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..0.008 rows=25 loops=1) Buffers: shared hit=1 Planning time: 7.586 ms Execution time: 10392.742 ms (68 rows) COMMIT; COMMIT