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 '1994-11-01'
	and o_orderdate < cast(date '1994-11-01' + 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=1185575.35..1185575.40 rows=20 width=176) (actual time=27511.890..27511.898 rows=20 loops=1)
   Buffers: shared hit=1043740 read=365383 dirtied=346 written=11739
   ->  Sort  (cost=1185575.35..1187001.02 rows=570270 width=176) (actual time=27511.887..27511.890 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=1043740 read=365383 dirtied=346 written=11739
         ->  HashAggregate  (cost=1164697.97..1170400.67 rows=570270 width=176) (actual time=26926.321..27351.626 rows=382163 loops=1)
               Buffers: shared hit=1043737 read=365383 dirtied=346 written=11739
               ->  Hash Join  (cost=398495.72..1150441.22 rows=570270 width=176) (actual time=5830.620..23765.906 rows=1149267 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1043737 read=365383 dirtied=346 written=11739
                     ->  Hash Join  (cost=398494.15..1142598.44 rows=570270 width=154) (actual time=5830.576..23231.864 rows=1149267 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1043736 read=365383 dirtied=346 written=11739
                           ->  Merge Join  (cost=329466.15..1062165.04 rows=570270 width=12) (actual time=4229.584..19525.958 rows=1149267 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1009448 read=364393 dirtied=346 written=11739
                                 ->  Sort  (cost=329466.13..330905.65 rows=575808 width=8) (actual time=4229.338..4380.301 rows=575160 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51537kB
                                       Buffers: shared hit=534 read=229559 dirtied=231
                                       ->  Bitmap Heap Scan on orders  (cost=12215.93..274375.05 rows=575808 width=8) (actual time=289.005..3975.014 rows=575160 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                             Buffers: shared hit=534 read=229559 dirtied=231
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12071.98 rows=575808 width=0) (actual time=211.231..211.231 rows=575740 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                                   Buffers: shared hit=533 read=1043
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..686940.76 rows=14870565 width=12) (actual time=0.107..12578.101 rows=14808321 loops=1)
                                       Buffers: shared hit=1008914 read=134834 dirtied=115 written=11739
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1599.067..1599.067 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=34288 read=990
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.012..633.651 rows=1500000 loops=1)
                                       Buffers: shared hit=34288 read=990
                     ->  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: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.010..0.019 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 27568.382 ms
(40 rows)

COMMIT;
COMMIT