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 BRUSHED STEEL' ) as all_nations group by o_year order by o_year; QUERY PLAN ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1791597.19..1791599.01 rows=727 width=38) (actual time=10613.783..10613.785 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=1799241 read=220810 dirtied=2231 written=399 -> HashAggregate (cost=1791549.91..1791562.64 rows=727 width=38) (actual time=10613.721..10613.723 rows=2 loops=1) Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone) Buffers: shared hit=1799238 read=220810 dirtied=2231 written=399 -> Hash Join (cost=39461.44..1791042.25 rows=25383 width=38) (actual time=892.783..10567.493 rows=24204 loops=1) Hash Cond: (supplier.s_nationkey = n2.n_nationkey) Buffers: shared hit=1799238 read=220810 dirtied=2231 written=399 -> Nested Loop (cost=39459.87..1790564.76 rows=25383 width=16) (actual time=892.727..10530.135 rows=24204 loops=1) Buffers: shared hit=1799234 read=220810 dirtied=2231 written=399 -> Hash Join (cost=39459.58..1782374.31 rows=25384 width=16) (actual time=892.713..10317.938 rows=24204 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=1726475 read=220810 dirtied=2231 written=399 -> Nested Loop (cost=428.90..1742613.83 rows=126920 width=20) (actual time=7.462..9335.890 rows=122276 loops=1) Buffers: shared hit=1586895 read=214242 dirtied=2231 written=392 -> Nested Loop (cost=428.46..1536925.81 rows=420064 width=16) (actual time=7.364..4614.980 rows=401933 loops=1) Buffers: shared hit=279240 read=192427 dirtied=2231 written=347 -> Bitmap Heap Scan on part (cost=427.90..28762.71 rows=13867 width=4) (actual time=7.289..189.019 rows=13411 loops=1) Recheck Cond: ((p_type)::text = 'ECONOMY BRUSHED STEEL'::text) Heap Blocks: exact=11429 Buffers: shared hit=1428 read=10085 written=20 -> Bitmap Index Scan on part_p_type_p_partkey_idx (cost=0.00..424.43 rows=13867 width=0) (actual time=5.071..5.071 rows=13411 loops=1) Index Cond: ((p_type)::text = 'ECONOMY BRUSHED STEEL'::text) Buffers: shared read=84 -> Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem (cost=0.56..108.45 rows=31 width=20) (actual time=0.030..0.316 rows=30 loops=13411) Index Cond: (l_partkey = part.p_partkey) Buffers: shared hit=277812 read=182342 dirtied=2231 written=327 -> 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=401933) Index Cond: ((o_orderkey = lineitem.l_orderkey) AND (o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date)) Buffers: shared hit=1307655 read=21815 written=45 -> Hash (cost=35280.69..35280.69 rows=300000 width=4) (actual time=880.904..880.904 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 14626kB Buffers: shared hit=139580 read=6568 written=7 -> Nested Loop (cost=906.18..35280.69 rows=300000 width=4) (actual time=20.939..781.448 rows=299493 loops=1) Buffers: shared hit=139580 read=6568 written=7 -> Hash Join (cost=1.07..2.47 rows=5 width=4) (actual time=0.048..0.081 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..0.015 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=0.015..0.017 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=18.373..145.813 rows=59899 loops=5) Recheck Cond: (c_nationkey = n1.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=139578 read=6568 written=7 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.010..12.010 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..0.008 rows=1 loops=24204) Index Cond: (s_suppkey = lineitem.l_suppkey) Buffers: shared hit=72759 -> Hash (cost=1.25..1.25 rows=25 width=30) (actual time=0.019..0.019 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..0.007 rows=25 loops=1) Buffers: shared hit=1 Planning time: 7.769 ms Execution time: 10614.654 ms (66 rows) COMMIT; COMMIT