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=1158823.51..1158823.56 rows=20 width=176) (actual time=29114.887..29114.894 rows=20 loops=1)
   Buffers: shared hit=728696 read=699338 dirtied=263 written=9808
   ->  Sort  (cost=1158823.51..1160266.39 rows=577153 width=176) (actual time=29114.884..29114.888 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=728696 read=699338 dirtied=263 written=9808
         ->  HashAggregate  (cost=1137694.14..1143465.67 rows=577153 width=176) (actual time=28525.332..28959.164 rows=381555 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=728693 read=699338 dirtied=263 written=9808
               ->  Hash Join  (cost=353922.20..1123265.32 rows=577153 width=176) (actual time=4479.137..26004.725 rows=1146697 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=728693 read=699338 dirtied=263 written=9808
                     ->  Hash Join  (cost=353920.63..1115327.90 rows=577153 width=154) (actual time=4479.093..25592.273 rows=1146697 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=728692 read=699338 dirtied=263 written=9808
                           ->  Hash Join  (cost=284892.63..1037642.61 rows=577153 width=12) (actual time=2741.578..22550.876 rows=1146697 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=728690 read=664062 dirtied=263 written=9779
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690959.45 rows=14938515 width=12) (actual time=0.057..14403.980 rows=14822651 loops=1)
                                       Buffers: shared hit=560757 read=599684 dirtied=114 written=9732
                                 ->  Hash  (cost=277568.44..277568.44 rows=585901 width=8) (actual time=2736.035..2736.035 rows=573799 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30607kB
                                       Buffers: shared hit=167933 read=64378 dirtied=149 written=47
                                       ->  Bitmap Heap Scan on orders  (cost=12725.92..277568.44 rows=585901 width=8) (actual time=293.677..2507.295 rows=573799 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                             Heap Blocks: exact=230651
                                             Buffers: shared hit=167933 read=64378 dirtied=149 written=47
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12579.44 rows=585901 width=0) (actual time=211.855..211.855 rows=579508 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                                   Buffers: shared read=1660 written=1
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1725.239..1725.239 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=29
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.022..884.848 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=29
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.026..0.026 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=0.011..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.889 ms
 Execution time: 29149.327 ms
(42 rows)

COMMIT;
COMMIT