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 '1993-05-01'
	and o_orderdate < cast(date '1993-05-01' + 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=1192410.19..1192410.24 rows=20 width=175) (actual time=59456.974..59456.980 rows=20 loops=1)
   Buffers: shared hit=712801 read=721237 dirtied=455 written=3329
   ->  Sort  (cost=1192410.19..1193869.76 rows=583827 width=175) (actual time=59456.970..59456.974 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=712801 read=721237 dirtied=455 written=3329
         ->  HashAggregate  (cost=1171036.50..1176874.77 rows=583827 width=175) (actual time=58893.340..59285.926 rows=381747 loops=1)
               Buffers: shared hit=712798 read=721237 dirtied=455 written=3329
               ->  Hash Join  (cost=403528.70..1156440.82 rows=583827 width=175) (actual time=7218.253..54772.194 rows=1148653 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=712798 read=721237 dirtied=455 written=3329
                     ->  Hash Join  (cost=403527.14..1148411.64 rows=583827 width=153) (actual time=7218.197..53839.499 rows=1148653 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=712797 read=721237 dirtied=455 written=3329
                           ->  Merge Join  (cost=334499.14..1067707.10 rows=583827 width=12) (actual time=3583.409..47616.020 rows=1148653 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=712795 read=685961 dirtied=455 written=553
                                 ->  Sort  (cost=334499.12..335987.35 rows=595291 width=8) (actual time=3583.218..3800.089 rows=574178 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51491kB
                                       Buffers: shared hit=228311 read=3308 dirtied=225
                                       ->  Bitmap Heap Scan on orders  (cost=12923.72..277401.08 rows=595291 width=8) (actual time=385.277..3281.770 rows=574178 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                             Buffers: shared hit=228311 read=3308 dirtied=225
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12774.89 rows=595291 width=0) (actual time=265.988..265.988 rows=578718 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                                   Buffers: shared hit=100 read=1550
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..687284.47 rows=14843518 width=12) (actual time=0.132..40157.703 rows=14822827 loops=1)
                                       Buffers: shared hit=484484 read=682653 dirtied=230 written=553
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3632.609..3632.609 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=2 read=35276 written=2776
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..2119.537 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=2776
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.024..0.024 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=0.007..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 59509.799 ms
(40 rows)

COMMIT;
COMMIT