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 '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + 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=1150637.97..1150638.02 rows=20 width=175) (actual time=27403.280..27403.286 rows=20 loops=1)
   Buffers: shared hit=795049 read=617475 written=7392
   ->  Sort  (cost=1150637.97..1152071.15 rows=573273 width=175) (actual time=27403.276..27403.280 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=795049 read=617475 written=7392
         ->  HashAggregate  (cost=1129650.65..1135383.38 rows=573273 width=175) (actual time=26911.070..27253.888 rows=381250 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=795046 read=617475 written=7392
               ->  Hash Join  (cost=351062.25..1115318.83 rows=573273 width=175) (actual time=4706.658..24828.109 rows=1147006 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=795046 read=617475 written=7392
                     ->  Hash Join  (cost=351060.68..1107434.76 rows=573273 width=153) (actual time=4706.616..24428.491 rows=1147006 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=795045 read=617475 written=7392
                           ->  Hash Join  (cost=282032.68..1029807.67 rows=573273 width=12) (actual time=2820.059..21783.425 rows=1147006 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=795033 read=582209 written=6545
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..686358.94 rows=14849000 width=12) (actual time=0.055..14038.330 rows=14808183 loops=1)
                                       Buffers: shared hit=632238 read=514844 written=3932
                                 ->  Hash  (cost=274779.00..274779.00 rows=580260 width=8) (actual time=2812.703..2812.703 rows=573502 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30595kB
                                       Buffers: shared hit=162795 read=67365 written=2613
                                       ->  Bitmap Heap Scan on orders  (cost=12300.10..274779.00 rows=580260 width=8) (actual time=394.108..2573.383 rows=573502 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=228590
                                             Buffers: shared hit=162795 read=67365 written=2613
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12155.03 rows=580260 width=0) (actual time=276.828..276.828 rows=574652 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared read=1570 written=62
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1875.107..1875.107 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=12 read=35266 written=847
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.015..970.213 rows=1500000 loops=1)
                                       Buffers: shared hit=12 read=35266 written=847
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.025..0.025 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..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.660 ms
 Execution time: 27431.517 ms
(42 rows)

COMMIT;
COMMIT