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 '1994-01-01'
	and o_orderdate < cast(date '1994-01-01' + 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=1156479.75..1156479.80 rows=20 width=176) (actual time=25460.812..25460.819 rows=20 loops=1)
   Buffers: shared hit=826173 read=597208 written=9773
   ->  Sort  (cost=1156479.75..1157867.21 rows=554984 width=176) (actual time=25460.808..25460.811 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=826173 read=597208 written=9773
         ->  HashAggregate  (cost=1136161.98..1141711.82 rows=554984 width=176) (actual time=25089.409..25320.541 rows=375126 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=826170 read=597208 written=9773
               ->  Hash Join  (cost=353065.56..1122287.38 rows=554984 width=176) (actual time=4035.204..22148.539 rows=1121466 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=826170 read=597208 written=9773
                     ->  Hash Join  (cost=353063.99..1114654.79 rows=554984 width=154) (actual time=4035.170..21749.371 rows=1121466 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=826169 read=597208 written=9773
                           ->  Hash Join  (cost=284035.99..1037302.03 rows=554984 width=12) (actual time=2275.074..19270.835 rows=1121466 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=825626 read=562473 written=9702
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691641.66 rows=14953327 width=12) (actual time=0.069..13491.562 rows=14822519 loops=1)
                                       Buffers: shared hit=625748 read=531302 written=9608
                                 ->  Hash  (cost=276993.13..276993.13 rows=563394 width=8) (actual time=2267.469..2267.469 rows=560646 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30093kB
                                       Buffers: shared hit=199878 read=31171 written=94
                                       ->  Bitmap Heap Scan on orders  (cost=12235.22..276993.13 rows=563394 width=8) (actual time=332.031..2082.750 rows=560646 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-01-01'::date) AND (o_orderdate < '1994-04-01'::date))
                                             Heap Blocks: exact=229425
                                             Buffers: shared hit=199878 read=31171 written=94
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12094.38 rows=563394 width=0) (actual time=236.013..236.013 rows=566864 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-01-01'::date) AND (o_orderdate < '1994-04-01'::date))
                                                   Buffers: shared read=1624 written=2
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1752.683..1752.683 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=543 read=34735 written=71
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.016..912.725 rows=1500000 loops=1)
                                       Buffers: shared hit=543 read=34735 written=71
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 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=0.006..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.880 ms
 Execution time: 25481.461 ms
(42 rows)

COMMIT;
COMMIT