BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_custkey,
	c_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue,
	c_acctbal,
	n_name,
	c_address,
	c_phone,
	c_comment
from
	customer,
	orders,
	lineitem,
	nation
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and o_orderdate >= date '1994-06-01'
	and o_orderdate < cast(date '1994-06-01' + interval '3 month' as date)
	and l_returnflag = 'R'
	and c_nationkey = n_nationkey
group by
	c_custkey,
	c_name,
	c_acctbal,
	c_phone,
	n_name,
	c_address,
	c_comment
order by
	revenue desc
LIMIT 20;
                                                                                               QUERY PLAN                                                                                                
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=2298232.22..2298232.27 rows=20 width=176) (actual time=30923.029..30923.034 rows=20 loops=1)
   Buffers: shared hit=894707 read=475079 dirtied=937 written=761
   ->  Sort  (cost=2298232.22..2299666.77 rows=573820 width=176) (actual time=30923.026..30923.030 rows=20 loops=1)
         Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
         Sort Method: top-N heapsort  Memory: 30kB
         Buffers: shared hit=894707 read=475079 dirtied=937 written=761
         ->  HashAggregate  (cost=2277224.87..2282963.07 rows=573820 width=176) (actual time=30550.875..30785.555 rows=381996 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=894704 read=475079 dirtied=937 written=761
               ->  Hash Join  (cost=347237.29..2262879.37 rows=573820 width=176) (actual time=6872.225..28569.501 rows=1149462 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=894704 read=475079 dirtied=937 written=761
                     ->  Hash Join  (cost=347235.72..2254987.78 rows=573820 width=154) (actual time=6872.194..28165.595 rows=1149462 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=894703 read=475079 dirtied=937 written=761
                           ->  Hash Join  (cost=278207.72..2177352.48 rows=573820 width=12) (actual time=5212.688..25772.833 rows=1149462 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=894701 read=439803 dirtied=937 written=541
                                 ->  Seq Scan on lineitem  (cost=0.00..1837000.11 rows=15041719 width=12) (actual time=0.012..17196.275 rows=14822519 loops=1)
                                       Filter: (l_returnflag = 'R'::bpchar)
                                       Rows Removed by Filter: 45222475
                                       Buffers: shared hit=662345 read=415841 dirtied=937 written=450
                                 ->  Hash  (cost=270969.07..270969.07 rows=579092 width=8) (actual time=5208.176..5208.176 rows=574700 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30642kB
                                       Buffers: shared hit=232356 read=23962 written=91
                                       ->  Bitmap Heap Scan on orders  (cost=5975.69..270969.07 rows=579092 width=8) (actual time=27.726..5016.674 rows=574700 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                             Rows Removed by Index Recheck: 14440300
                                             Heap Blocks: lossy=256307
                                             Buffers: shared hit=232356 read=23962 written=91
                                             ->  Bitmap Index Scan on orders_o_orderkey_o_orderdate_brin_idx  (cost=0.00..5830.92 rows=579092 width=0) (actual time=27.552..27.552 rows=2563840 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                                   Buffers: shared hit=3 read=8
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1650.585..1650.585 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=220
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.006..801.290 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=220
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.111 ms
 Execution time: 30936.670 ms
(45 rows)

COMMIT;
COMMIT