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=1152193.71..1152193.76 rows=20 width=175) (actual time=24682.639..24682.647 rows=20 loops=1)
   Buffers: shared hit=1098815 read=319865 written=4716
   ->  Sort  (cost=1152193.71..1153629.19 rows=574192 width=175) (actual time=24682.635..24682.639 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=1098815 read=319865 written=4716
         ->  HashAggregate  (cost=1131172.74..1136914.66 rows=574192 width=175) (actual time=24292.526..24538.770 rows=381230 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=1098812 read=319865 written=4716
               ->  Hash Join  (cost=351337.07..1116817.94 rows=574192 width=175) (actual time=4614.154..21964.669 rows=1146953 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1098812 read=319865 written=4716
                     ->  Hash Join  (cost=351335.50..1108921.24 rows=574192 width=153) (actual time=4614.097..21572.196 rows=1146953 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1098811 read=319865 written=4716
                           ->  Hash Join  (cost=282307.50..1031280.36 rows=574192 width=12) (actual time=2687.549..18749.877 rows=1146953 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1098808 read=284590 written=2799
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..687458.38 rows=14872797 width=12) (actual time=0.061..12708.828 rows=14808453 loops=1)
                                       Buffers: shared hit=932626 read=220392 written=270
                                 ->  Hash  (cost=275046.59..275046.59 rows=580838 width=8) (actual time=2683.109..2683.109 rows=573479 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30594kB
                                       Buffers: shared hit=166182 read=64198 written=2529
                                       ->  Bitmap Heap Scan on orders  (cost=12306.02..275046.59 rows=580838 width=8) (actual time=305.452..2494.846 rows=573479 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=228810
                                             Buffers: shared hit=166182 read=64198 written=2529
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12160.82 rows=580838 width=0) (actual time=218.627..218.627 rows=575289 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared hit=46 read=1524 written=87
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1913.500..1913.500 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=3 read=35275 written=1917
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.015..953.976 rows=1500000 loops=1)
                                       Buffers: shared hit=3 read=35275 written=1917
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.034..0.034 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..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.462 ms
 Execution time: 24711.109 ms
(42 rows)

COMMIT;
COMMIT