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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1192156.56..1192156.61 rows=20 width=175) (actual time=101113.096..101113.104 rows=20 loops=1)
   Buffers: shared hit=543350 read=882403
   ->  Sort  (cost=1192156.56..1193563.25 rows=562674 width=175) (actual time=101113.092..101113.096 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=543350 read=882403
         ->  HashAggregate  (cost=1171557.27..1177184.01 rows=562674 width=175) (actual time=100576.595..100946.630 rows=378906 loops=1)
               Buffers: shared hit=543347 read=882403
               ->  Hash Join  (cost=399672.43..1157490.42 rows=562674 width=175) (actual time=11745.862..96135.860 rows=1136474 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=543347 read=882403
                     ->  Hash Join  (cost=399670.87..1149752.09 rows=562674 width=153) (actual time=11745.824..95110.240 rows=1136474 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=543346 read=882403
                           ->  Merge Join  (cost=330642.87..1069470.61 rows=562674 width=12) (actual time=8343.415..88398.399 rows=1136474 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=508221 read=882250
                                 ->  Sort  (cost=330642.86..332062.06 rows=567678 width=8) (actual time=8343.236..8600.757 rows=567980 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51201kB
                                       Buffers: shared hit=229389 read=1706
                                       ->  Bitmap Heap Scan on orders  (cost=12324.68..276387.85 rows=567678 width=8) (actual time=698.853..7075.080 rows=567980 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Buffers: shared hit=229389 read=1706
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12182.76 rows=567678 width=0) (actual time=588.107..588.107 rows=572397 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared read=1637
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..692860.39 rows=15001571 width=12) (actual time=0.161..75774.439 rows=14822845 loops=1)
                                       Buffers: shared hit=278832 read=880544
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3400.767..3400.767 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35125 read=153
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.012..1709.247 rows=1500000 loops=1)
                                       Buffers: shared hit=35125 read=153
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.018..0.018 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=0.006..0.008 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 101193.246 ms
(40 rows)

COMMIT;
COMMIT