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=1147279.68..1147279.73 rows=20 width=175) (actual time=31035.219..31035.226 rows=20 loops=1)
   Buffers: shared hit=1268687 read=137245 written=430
   ->  Sort  (cost=1147279.68..1148689.13 rows=563781 width=175) (actual time=31035.215..31035.217 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=1268687 read=137245 written=430
         ->  HashAggregate  (cost=1126639.86..1132277.67 rows=563781 width=175) (actual time=30672.304..30890.467 rows=381278 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=1268684 read=137245 written=430
               ->  Hash Join  (cost=350395.16..1112545.33 rows=563781 width=175) (actual time=8494.613..28253.886 rows=1147051 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1268684 read=137245 written=430
                     ->  Hash Join  (cost=350393.60..1104791.78 rows=563781 width=153) (actual time=8494.550..27783.518 rows=1147051 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1268683 read=137245 written=430
                           ->  Hash Join  (cost=281365.60..1027307.06 rows=563781 width=12) (actual time=6800.013..24812.550 rows=1147051 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1233405 read=137245 written=430
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..684770.27 rows=14809019 width=12) (actual time=0.127..12202.311 rows=14808323 loops=1)
                                       Buffers: shared hit=1067988 read=72731 written=114
                                 ->  Hash  (cost=274219.89..274219.89 rows=571622 width=8) (actual time=6793.623..6793.623 rows=573503 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30595kB
                                       Buffers: shared hit=165417 read=64514 written=316
                                       ->  Bitmap Heap Scan on orders  (cost=12123.56..274219.89 rows=571622 width=8) (actual time=629.556..6406.937 rows=573503 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=228361
                                             Buffers: shared hit=165417 read=64514 written=316
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11980.66 rows=571622 width=0) (actual time=473.412..473.412 rows=574082 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared hit=1 read=1569
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1672.788..1672.788 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.041..744.058 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  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=0.010..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.443 ms
 Execution time: 31050.141 ms
(42 rows)

COMMIT;
COMMIT