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 '1993-03-01'
	and o_orderdate < cast(date '1993-03-01' + 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=1181838.51..1181838.56 rows=20 width=175) (actual time=45349.048..45349.055 rows=20 loops=1)
   Buffers: shared hit=988592 read=421286 written=38676
   ->  Sort  (cost=1181838.51..1183263.52 rows=570006 width=175) (actual time=45349.044..45349.050 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=988592 read=421286 written=38676
         ->  HashAggregate  (cost=1160970.79..1166670.85 rows=570006 width=175) (actual time=44818.490..45194.284 rows=381994 loops=1)
               Buffers: shared hit=988589 read=421286 written=38676
               ->  Hash Join  (cost=399489.65..1146720.64 rows=570006 width=175) (actual time=5859.687..39913.409 rows=1148304 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=988589 read=421286 written=38676
                     ->  Hash Join  (cost=399488.09..1138881.50 rows=570006 width=153) (actual time=5859.628..39127.161 rows=1148304 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=988588 read=421286 written=38676
                           ->  Merge Join  (cost=330460.09..1058453.38 rows=570006 width=12) (actual time=3355.487..33582.100 rows=1148304 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=953310 read=421286 written=38676
                                 ->  Sort  (cost=330460.07..331913.02 rows=581183 width=8) (actual time=3355.285..3580.606 rows=573444 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51457kB
                                       Buffers: shared hit=228466 read=1571
                                       ->  Bitmap Heap Scan on orders  (cost=12323.02..274815.77 rows=581183 width=8) (actual time=784.894..2653.801 rows=573444 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                             Buffers: shared hit=228466 read=1571
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12177.73 rows=581183 width=0) (actual time=592.524..592.524 rows=574514 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                                   Buffers: shared read=1571
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..682535.03 rows=14740923 width=12) (actual time=0.117..26556.680 rows=14808171 loops=1)
                                       Buffers: shared hit=724844 read=419715 written=38676
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2502.149..2502.149 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.021..993.996 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.026..0.026 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=0.009..0.016 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 45456.950 ms
(40 rows)

COMMIT;
COMMIT