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=1154744.37..1154744.42 rows=20 width=176) (actual time=26027.955..26027.962 rows=20 loops=1)
   Buffers: shared hit=891827 read=529932 written=410
   ->  Sort  (cost=1154744.37..1156169.52 rows=570060 width=176) (actual time=26027.952..26027.955 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=891827 read=529932 written=410
         ->  HashAggregate  (cost=1133874.68..1139575.28 rows=570060 width=176) (actual time=25647.023..25888.400 rows=381934 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=891824 read=529932 written=410
               ->  Hash Join  (cost=352779.58..1119623.18 rows=570060 width=176) (actual time=4802.871..22725.892 rows=1148265 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=891824 read=529932 written=410
                     ->  Hash Join  (cost=352778.02..1111783.30 rows=570060 width=154) (actual time=4802.825..22319.980 rows=1148265 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=891823 read=529932 written=410
                           ->  Hash Join  (cost=283750.02..1034204.40 rows=570060 width=12) (actual time=2939.225..19657.306 rows=1148265 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=891821 read=494656 written=344
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688901.31 rows=14894107 width=12) (actual time=0.072..13179.482 rows=14823054 loops=1)
                                       Buffers: shared hit=728500 read=426520 written=238
                                 ->  Hash  (cost=276515.76..276515.76 rows=578706 width=8) (actual time=2620.252..2620.252 rows=574361 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30628kB
                                       Buffers: shared hit=163321 read=68136 written=106
                                       ->  Bitmap Heap Scan on orders  (cost=12540.17..276515.76 rows=578706 width=8) (actual time=293.335..2421.455 rows=574361 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                             Heap Blocks: exact=229815
                                             Buffers: shared hit=163321 read=68136 written=106
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12395.50 rows=578706 width=0) (actual time=212.282..212.282 rows=578200 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                                   Buffers: shared read=1642 written=1
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1847.830..1847.830 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=66
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.021..925.109 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=66
                     ->  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=0.007..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.928 ms
 Execution time: 26052.192 ms
(42 rows)

COMMIT;
COMMIT