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 '1994-08-01'
	and o_orderdate < cast(date '1994-08-01' + 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=1154399.02..1154399.07 rows=20 width=176) (actual time=27669.473..27669.480 rows=20 loops=1)
   Buffers: shared hit=713755 read=707453 dirtied=1447 written=2842
   ->  Sort  (cost=1154399.02..1155836.19 rows=574868 width=176) (actual time=27669.469..27669.473 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=713755 read=707453 dirtied=1447 written=2842
         ->  HashAggregate  (cost=1133353.31..1139101.99 rows=574868 width=176) (actual time=27192.555..27516.990 rows=381547 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=713752 read=707453 dirtied=1447 written=2842
               ->  Hash Join  (cost=352685.69..1118981.61 rows=574868 width=176) (actual time=5071.462..25006.799 rows=1146799 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=713752 read=707453 dirtied=1447 written=2842
                     ->  Hash Join  (cost=352684.13..1111075.61 rows=574868 width=154) (actual time=5071.419..24595.202 rows=1146799 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=713751 read=707453 dirtied=1447 written=2842
                           ->  Hash Join  (cost=283656.13..1033424.59 rows=574868 width=12) (actual time=3022.375..21614.333 rows=1146799 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=713748 read=672178 dirtied=1447 written=2829
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688222.55 rows=14879378 width=12) (actual time=0.062..14128.394 rows=14822937 loops=1)
                                       Buffers: shared hit=577567 read=576983 dirtied=1149 written=2715
                                 ->  Hash  (cost=276360.91..276360.91 rows=583583 width=8) (actual time=3013.758..3013.758 rows=573832 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30608kB
                                       Buffers: shared hit=136181 read=95195 dirtied=298 written=114
                                       ->  Bitmap Heap Scan on orders  (cost=12566.16..276360.91 rows=583583 width=8) (actual time=302.519..2774.866 rows=573832 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                             Heap Blocks: exact=229742
                                             Buffers: shared hit=136181 read=95195 dirtied=298 written=114
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12420.26 rows=583583 width=0) (actual time=219.720..219.720 rows=577238 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                                   Buffers: shared read=1634 written=2
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1953.988..1953.988 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=3 read=35275 written=13
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.033..969.309 rows=1500000 loops=1)
                                       Buffers: shared hit=3 read=35275 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=0.007..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.811 ms
 Execution time: 27709.939 ms
(42 rows)

COMMIT;
COMMIT