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=1153594.17..1153594.22 rows=20 width=176) (actual time=32351.296..32351.303 rows=20 loops=1)
   Buffers: shared hit=773158 read=645899 dirtied=778 written=10602
   ->  Sort  (cost=1153594.17..1155017.92 rows=569497 width=176) (actual time=32351.292..32351.295 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=773158 read=645899 dirtied=778 written=10602
         ->  HashAggregate  (cost=1132745.09..1138440.06 rows=569497 width=176) (actual time=31936.233..32208.637 rows=381273 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=773155 read=645899 dirtied=778 written=10602
               ->  Hash Join  (cost=352419.88..1118507.67 rows=569497 width=176) (actual time=4198.585..25649.153 rows=1147097 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=773155 read=645899 dirtied=778 written=10602
                     ->  Hash Join  (cost=352418.32..1110675.52 rows=569497 width=154) (actual time=4198.552..25239.894 rows=1147097 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=773154 read=645899 dirtied=778 written=10602
                           ->  Hash Join  (cost=283390.32..1033105.07 rows=569497 width=12) (actual time=2406.163..22259.600 rows=1147097 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=773151 read=610624 dirtied=778 written=10551
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688222.55 rows=14879378 width=12) (actual time=0.063..14416.403 rows=14808293 loops=1)
                                       Buffers: shared hit=596775 read=555638 dirtied=674 written=9967
                                 ->  Hash  (cost=276163.24..276163.24 rows=578131 width=8) (actual time=2400.562..2400.562 rows=573576 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30598kB
                                       Buffers: shared hit=176376 read=54986 dirtied=104 written=584
                                       ->  Bitmap Heap Scan on orders  (cost=12450.28..276163.24 rows=578131 width=8) (actual time=275.376..2210.087 rows=573576 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=229731
                                             Buffers: shared hit=176376 read=54986 dirtied=104 written=584
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12305.75 rows=578131 width=0) (actual time=197.364..197.364 rows=577555 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared read=1631 written=1
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1779.102..1779.102 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=3 read=35275 written=51
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.016..889.928 rows=1500000 loops=1)
                                       Buffers: shared hit=3 read=35275 written=51
                     ->  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..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.302 ms
 Execution time: 32386.115 ms
(42 rows)

COMMIT;
COMMIT