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 '1994-06-01'
	and o_orderdate < cast(date '1994-06-01' + 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=1195621.66..1195621.71 rows=20 width=176) (actual time=33629.950..33629.958 rows=20 loops=1)
   Buffers: shared hit=1105773 read=316776 written=34530
   ->  Sort  (cost=1195621.66..1197082.38 rows=584289 width=176) (actual time=33629.945..33629.949 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=1105773 read=316776 written=34530
         ->  HashAggregate  (cost=1174231.05..1180073.94 rows=584289 width=176) (actual time=33072.389..33452.025 rows=381760 loops=1)
               Buffers: shared hit=1105770 read=316776 written=34530
               ->  Hash Join  (cost=403058.46..1159623.82 rows=584289 width=176) (actual time=4559.055..28955.539 rows=1148406 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1105770 read=316776 written=34530
                     ->  Hash Join  (cost=403056.90..1151588.29 rows=584289 width=154) (actual time=4559.013..28265.481 rows=1148406 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1105769 read=316776 written=34530
                           ->  Merge Join  (cost=334028.90..1070874.51 rows=584289 width=12) (actual time=2300.700..23834.154 rows=1148406 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1070491 read=316776 written=34530
                                 ->  Sort  (cost=334028.88..335508.65 rows=591908 width=8) (actual time=2300.627..2477.930 rows=574198 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51492kB
                                       Buffers: shared hit=230117 read=1659
                                       ->  Bitmap Heap Scan on orders  (cost=12853.04..277279.66 rows=591908 width=8) (actual time=431.074..2052.101 rows=574198 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                             Buffers: shared hit=230117 read=1659
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12705.06 rows=591908 width=0) (actual time=261.110..261.110 rows=579480 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                                   Buffers: shared hit=2 read=1659
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690692.79 rows=14940165 width=12) (actual time=0.054..18076.279 rows=14807950 loops=1)
                                       Buffers: shared hit=840374 read=315117 written=34530
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2256.379..2256.379 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.015..1008.309 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.022..0.022 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=0.007..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 33700.479 ms
(40 rows)

COMMIT;
COMMIT