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 '1994-02-01'
	and o_orderdate < cast(date '1994-02-01' + 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=2288759.89..2288759.94 rows=20 width=176) (actual time=29741.888..29741.895 rows=20 loops=1)
   Buffers: shared hit=1005784 read=360030 written=6
   ->  Sort  (cost=2288759.89..2290138.98 rows=551637 width=176) (actual time=29741.885..29741.887 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=1005784 read=360030 written=6
         ->  HashAggregate  (cost=2268564.66..2274081.03 rows=551637 width=176) (actual time=29413.681..29608.007 rows=371940 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=1005781 read=360030 written=6
               ->  Hash Join  (cost=345633.59..2254773.73 rows=551637 width=176) (actual time=6383.527..27552.659 rows=1109444 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1005781 read=360030 written=6
                     ->  Hash Join  (cost=345632.03..2247187.16 rows=551637 width=154) (actual time=6383.499..27163.580 rows=1109444 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1005780 read=360030 written=6
                           ->  Hash Join  (cost=276604.03..2169884.61 rows=551637 width=12) (actual time=5048.662..25169.200 rows=1109444 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=970502 read=360030 written=6
                                 ->  Seq Scan on lineitem  (cost=0.00..1831525.85 rows=14996895 width=12) (actual time=0.012..17080.354 rows=14807964 loops=1)
                                       Filter: (l_returnflag = 'R'::bpchar)
                                       Rows Removed by Filter: 45175958
                                       Buffers: shared hit=723320 read=351653 written=6
                                 ->  Hash  (cost=269645.08..269645.08 rows=556716 width=8) (actual time=5043.859..5043.859 rows=554270 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 29844kB
                                       Buffers: shared hit=247182 read=8377
                                       ->  Bitmap Heap Scan on orders  (cost=5746.34..269645.08 rows=556716 width=8) (actual time=27.565..4862.971 rows=554270 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                             Rows Removed by Index Recheck: 14445730
                                             Heap Blocks: lossy=255548
                                             Buffers: shared hit=247182 read=8377
                                             ->  Bitmap Index Scan on orders_o_orderkey_o_orderdate_brin_idx  (cost=0.00..5607.16 rows=556716 width=0) (actual time=27.398..27.398 rows=2556160 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                                   Buffers: shared hit=11
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1328.675..1328.675 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.009..563.508 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  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  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.007 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.793 ms
 Execution time: 29755.255 ms
(45 rows)

COMMIT;
COMMIT