BEGIN; BEGIN EXPLAIN (ANALYZE, BUFFERS) select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AFRICA' and o_orderdate >= date '1993-01-01' and o_orderdate < date '1993-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=1879805.25..1879805.32 rows=25 width=34) (actual time=15849.434..15849.435 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=2227254 read=494029 dirtied=507 written=13962 -> HashAggregate (cost=1879804.42..1879804.67 rows=25 width=34) (actual time=15849.361..15849.363 rows=5 loops=1) Group Key: nation.n_name Buffers: shared hit=2227251 read=494029 dirtied=507 written=13962 -> Hash Join (cost=93800.58..1879067.37 rows=73705 width=34) (actual time=2482.224..15766.898 rows=72485 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=2227251 read=494029 dirtied=507 written=13962 -> Nested Loop (cost=89121.58..1859817.49 rows=1844511 width=46) (actual time=2417.618..14492.660 rows=1823556 loops=1) Buffers: shared hit=2225069 read=494029 dirtied=507 written=13962 -> Hash Join (cost=89121.01..393534.37 rows=461237 width=38) (actual time=2417.528..7700.054 rows=455462 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=135783 read=273503 dirtied=507 written=8492 -> Bitmap Heap Scan on orders (cost=50078.84..341231.63 rows=2306186 width=8) (actual time=1367.180..5099.699 rows=2277198 loops=1) Recheck Cond: ((o_orderdate >= '1993-01-01'::date) AND (o_orderdate < '1994-01-01 00:00:00'::timestamp without time zone)) Heap Blocks: exact=256548 Buffers: shared hit=25735 read=237402 dirtied=507 written=8418 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..49502.29 rows=2306186 width=0) (actual time=1232.736..1232.736 rows=2306268 loops=1) Index Cond: ((o_orderdate >= '1993-01-01'::date) AND (o_orderdate < '1994-01-01 00:00:00'::timestamp without time zone)) Buffers: shared read=6589 written=12 -> Hash (cost=35292.17..35292.17 rows=300000 width=38) (actual time=1046.401..1046.401 rows=299493 loops=1) Buckets: 524288 Batches: 1 Memory Usage: 25155kB Buffers: shared hit=110048 read=36101 written=74 -> Nested Loop (cost=905.25..35292.17 rows=300000 width=38) (actual time=20.928..916.160 rows=299493 loops=1) Buffers: shared hit=110048 read=36101 written=74 -> Nested Loop (cost=0.14..13.95 rows=5 width=30) (actual time=0.042..0.114 rows=5 loops=1) Join Filter: (nation.n_regionkey = region.r_regionkey) Rows Removed by Join Filter: 20 Buffers: shared hit=3 -> Index Scan using pk_nation on nation (cost=0.14..12.51 rows=25 width=34) (actual time=0.009..0.027 rows=25 loops=1) Buffers: shared hit=2 -> Materialize (cost=0.00..1.07 rows=1 width=4) (actual time=0.001..0.002 rows=1 loops=25) Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.015..0.020 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=18.644..170.096 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Heap Blocks: exact=145314 Buffers: shared hit=110045 read=36101 written=74 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.11 rows=60000 width=0) (actual time=12.053..12.053 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=825 written=2 -> Index Scan using pk_lineitem on lineitem (cost=0.56..3.03 rows=15 width=16) (actual time=0.012..0.013 rows=4 loops=455462) Index Cond: (l_orderkey = orders.o_orderkey) Buffers: shared hit=2089286 read=220526 written=5470 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=62.456..62.456 rows=100000 loops=1) Buckets: 131072 Batches: 1 Memory Usage: 4931kB Buffers: shared hit=2179 -> Seq Scan on supplier (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.009..34.561 rows=100000 loops=1) Buffers: shared hit=2179 Planning time: 6.779 ms Execution time: 15852.369 ms (56 rows) COMMIT; COMMIT