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 '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + 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=1190289.56..1190289.61 rows=20 width=175) (actual time=68413.971..68413.979 rows=20 loops=1)
   Buffers: shared hit=619859 read=804311 written=17857
   ->  Sort  (cost=1190289.56..1191708.85 rows=567713 width=175) (actual time=68413.967..68413.970 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=619859 read=804311 written=17857
         ->  HashAggregate  (cost=1169505.80..1175182.93 rows=567713 width=175) (actual time=67829.150..68227.858 rows=381586 loops=1)
               Buffers: shared hit=619856 read=804311 written=17857
               ->  Hash Join  (cost=401741.93..1155312.97 rows=567713 width=175) (actual time=8868.758..62740.235 rows=1148224 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=619856 read=804311 written=17857
                     ->  Hash Join  (cost=401740.36..1147505.35 rows=567713 width=153) (actual time=8868.612..61812.204 rows=1148224 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=619855 read=804311 written=17857
                           ->  Merge Join  (cost=332712.36..1067123.09 rows=567713 width=12) (actual time=6181.862..56524.565 rows=1148224 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=584702 read=804186 written=17857
                                 ->  Sort  (cost=332712.34..334159.47 rows=578852 width=8) (actual time=6181.719..6409.804 rows=574181 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51491kB
                                       Buffers: shared hit=211762 read=20544
                                       ->  Bitmap Heap Scan on orders  (cost=12571.22..277308.00 rows=578852 width=8) (actual time=314.342..5843.023 rows=574181 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Buffers: shared hit=211762 read=20544
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12426.51 rows=578852 width=0) (actual time=234.402..234.402 rows=579875 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared read=1659
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..688656.56 rows=14873123 width=12) (actual time=0.108..46301.979 rows=14822651 loops=1)
                                       Buffers: shared hit=372940 read=783642 written=17857
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2684.876..2684.876 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35153 read=125
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.015..1414.544 rows=1500000 loops=1)
                                       Buffers: shared hit=35153 read=125
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.117..0.117 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.099..0.104 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 68473.441 ms
(40 rows)

COMMIT;
COMMIT