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 '1994-07-01'
	and o_orderdate < cast(date '1994-07-01' + 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=1146286.23..1146286.28 rows=20 width=175) (actual time=26084.682..26084.689 rows=20 loops=1)
   Buffers: shared hit=1217555 read=191588 dirtied=329 written=1176
   ->  Sort  (cost=1146286.23..1147685.42 rows=559675 width=175) (actual time=26084.678..26084.682 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=1217555 read=191588 dirtied=329 written=1176
         ->  HashAggregate  (cost=1125796.73..1131393.48 rows=559675 width=175) (actual time=25531.869..25929.969 rows=381218 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=1217552 read=191588 dirtied=329 written=1176
               ->  Hash Join  (cost=350212.85..1111804.86 rows=559675 width=175) (actual time=7431.998..22659.355 rows=1145713 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1217552 read=191588 dirtied=329 written=1176
                     ->  Hash Join  (cost=350211.28..1104107.77 rows=559675 width=153) (actual time=7431.843..22289.379 rows=1145713 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1217551 read=191588 dirtied=329 written=1176
                           ->  Hash Join  (cost=281183.28..1026684.64 rows=559675 width=12) (actual time=5590.482..19430.111 rows=1145713 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1183246 read=190615 dirtied=329 written=1176
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..684409.70 rows=14798758 width=12) (actual time=0.102..8869.859 rows=14808323 loops=1)
                                       Buffers: shared hit=1099407 read=44341 dirtied=115 written=1176
                                 ->  Hash  (cost=274084.70..274084.70 rows=567852 width=8) (actual time=5580.931..5580.931 rows=573256 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30585kB
                                       Buffers: shared hit=83839 read=146274 dirtied=214
                                       ->  Bitmap Heap Scan on orders  (cost=12044.92..274084.70 rows=567852 width=8) (actual time=518.209..5206.155 rows=573256 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                             Heap Blocks: exact=228543
                                             Buffers: shared hit=83839 read=146274 dirtied=214
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11902.95 rows=567852 width=0) (actual time=397.235..397.235 rows=573807 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                                   Buffers: shared hit=1 read=1569
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1828.455..1828.455 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=34305 read=973
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..707.868 rows=1500000 loops=1)
                                       Buffers: shared hit=34305 read=973
                     ->  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..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.566 ms
 Execution time: 26120.944 ms
(42 rows)

COMMIT;
COMMIT