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=1156129.66..1156129.71 rows=20 width=175) (actual time=30287.858..30287.866 rows=20 loops=1)
   Buffers: shared hit=759592 read=662191 dirtied=222 written=709
   ->  Sort  (cost=1156129.66..1157566.60 rows=574777 width=175) (actual time=30287.853..30287.856 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=759592 read=662191 dirtied=222 written=709
         ->  HashAggregate  (cost=1135087.28..1140835.05 rows=574777 width=175) (actual time=29500.259..30041.774 rows=382277 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=759589 read=662191 dirtied=222 written=709
               ->  Hash Join  (cost=352977.34..1120717.85 rows=574777 width=175) (actual time=4489.550..27126.228 rows=1149487 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=759589 read=662191 dirtied=222 written=709
                     ->  Hash Join  (cost=352975.78..1112813.11 rows=574777 width=153) (actual time=4489.498..26674.714 rows=1149487 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=759588 read=662191 dirtied=222 written=709
                           ->  Hash Join  (cost=283947.78..1035163.45 rows=574777 width=12) (actual time=2628.381..23657.670 rows=1149487 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=759586 read=626915 dirtied=222 written=655
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689546.95 rows=14912372 width=12) (actual time=0.087..15288.708 rows=14823054 loops=1)
                                       Buffers: shared hit=586531 read=568489 written=585
                                 ->  Hash  (cost=276662.60..276662.60 rows=582779 width=8) (actual time=2622.514..2622.514 rows=574042 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30616kB
                                       Buffers: shared hit=173055 read=58426 dirtied=222 written=70
                                       ->  Bitmap Heap Scan on orders  (cost=12625.92..276662.60 rows=582779 width=8) (actual time=319.213..2414.481 rows=574042 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                             Heap Blocks: exact=229834
                                             Buffers: shared hit=173055 read=58426 dirtied=222 written=70
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12480.23 rows=582779 width=0) (actual time=232.654..232.654 rows=577965 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                                   Buffers: shared read=1647 written=8
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1852.553..1852.553 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=54
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..983.744 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=54
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.030..0.030 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=0.009..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 7.093 ms
 Execution time: 30315.501 ms
(42 rows)

COMMIT;
COMMIT