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 '1993-06-01'
	and o_orderdate < cast(date '1993-06-01' + 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=1155018.00..1155018.05 rows=20 width=176) (actual time=22530.047..22530.052 rows=20 loops=1)
   Buffers: shared hit=606537 read=808174 dirtied=1103 written=233
   ->  Sort  (cost=1155018.00..1156440.05 rows=568820 width=176) (actual time=22530.044..22530.046 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=606537 read=808174 dirtied=1103 written=233
         ->  HashAggregate  (cost=1134193.70..1139881.90 rows=568820 width=176) (actual time=22105.178..22390.864 rows=381241 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=606534 read=808174 dirtied=1103 written=233
               ->  Hash Join  (cost=353023.03..1119973.20 rows=568820 width=176) (actual time=3220.337..20273.435 rows=1146395 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=606534 read=808174 dirtied=1103 written=233
                     ->  Hash Join  (cost=353021.46..1112150.36 rows=568820 width=154) (actual time=3220.306..19891.974 rows=1146395 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=606533 read=808174 dirtied=1103 written=233
                           ->  Hash Join  (cost=283993.46..1034590.06 rows=568820 width=12) (actual time=1650.925..17658.994 rows=1146395 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=606531 read=772898 dirtied=1103 written=220
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689056.88 rows=14893854 width=12) (actual time=0.069..12854.030 rows=14807964 loops=1)
                                       Buffers: shared hit=382187 read=765581 dirtied=1103 written=220
                                 ->  Hash  (cost=276767.67..276767.67 rows=578029 width=8) (actual time=1645.606..1645.606 rows=573702 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30603kB
                                       Buffers: shared hit=224344 read=7317
                                       ->  Bitmap Heap Scan on orders  (cost=12549.23..276767.67 rows=578029 width=8) (actual time=231.783..1485.445 rows=573702 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Heap Blocks: exact=230008
                                             Buffers: shared hit=224344 read=7317
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12404.73 rows=578029 width=0) (actual time=162.791..162.791 rows=578819 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1653
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1559.033..1559.033 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=13
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.013..775.403 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=13
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 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: 4.541 ms
 Execution time: 22546.185 ms
(42 rows)

COMMIT;
COMMIT