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 '1993-07-01'
	and o_orderdate < cast(date '1993-07-01' + 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=1158680.47..1158680.52 rows=20 width=176) (actual time=27801.489..27801.495 rows=20 loops=1)
   Buffers: shared hit=764346 read=664022 dirtied=1873 written=5266
   ->  Sort  (cost=1158680.47..1160111.06 rows=572236 width=176) (actual time=27801.485..27801.486 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=764346 read=664022 dirtied=1873 written=5266
         ->  HashAggregate  (cost=1137731.11..1143453.47 rows=572236 width=176) (actual time=27274.009..27649.441 rows=381633 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=764343 read=664022 dirtied=1873 written=5266
               ->  Hash Join  (cost=353651.55..1123425.21 rows=572236 width=176) (actual time=4673.376..24217.485 rows=1147161 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=764343 read=664022 dirtied=1873 written=5266
                     ->  Hash Join  (cost=353649.99..1115555.41 rows=572236 width=154) (actual time=4673.331..23793.331 rows=1147161 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=764342 read=664022 dirtied=1873 written=5266
                           ->  Hash Join  (cost=284621.99..1037943.87 rows=572236 width=12) (actual time=2626.403..20452.019 rows=1147161 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=764340 read=628746 dirtied=1873 written=1773
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691533.92 rows=14950942 width=12) (actual time=0.067..13909.329 rows=14807792 loops=1)
                                       Buffers: shared hit=596047 read=564871 dirtied=1873 written=1120
                                 ->  Hash  (cost=277366.22..277366.22 rows=580427 width=8) (actual time=2620.347..2620.347 rows=573787 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30606kB
                                       Buffers: shared hit=168293 read=63875 written=653
                                       ->  Bitmap Heap Scan on orders  (cost=12605.81..277366.22 rows=580427 width=8) (actual time=311.933..2419.072 rows=573787 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                             Heap Blocks: exact=230508
                                             Buffers: shared hit=168293 read=63875 written=653
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12460.70 rows=580427 width=0) (actual time=227.642..227.642 rows=580443 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                                   Buffers: shared hit=99 read=1561 written=151
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2022.321..2022.321 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=3493
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.025..987.077 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=3493
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 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..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.578 ms
 Execution time: 27836.245 ms
(42 rows)

COMMIT;
COMMIT