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=1189359.83..1189359.88 rows=20 width=175) (actual time=29675.499..29675.509 rows=20 loops=1)
   Buffers: shared hit=1347698 read=76743 dirtied=117
   ->  Sort  (cost=1189359.83..1190783.18 rows=569342 width=175) (actual time=29675.494..29675.499 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=1347698 read=76743 dirtied=117
         ->  HashAggregate  (cost=1168516.42..1174209.84 rows=569342 width=175) (actual time=29045.540..29462.568 rows=382422 loops=1)
               Buffers: shared hit=1347695 read=76743 dirtied=117
               ->  Hash Join  (cost=399850.51..1154282.87 rows=569342 width=175) (actual time=5168.301..25234.180 rows=1150485 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1347695 read=76743 dirtied=117
                     ->  Hash Join  (cost=399848.94..1146452.85 rows=569342 width=153) (actual time=5168.245..24588.349 rows=1150485 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1347694 read=76743 dirtied=117
                           ->  Merge Join  (cost=330820.94..1066038.01 rows=569342 width=12) (actual time=2713.669..19768.236 rows=1150485 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1312416 read=76743 dirtied=117
                                 ->  Sort  (cost=330820.94..332260.89 rows=575978 width=8) (actual time=2713.464..2881.144 rows=575745 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51565kB
                                       Buffers: shared hit=218990 read=12263
                                       ->  Bitmap Heap Scan on orders  (cost=12285.70..275712.37 rows=575978 width=8) (actual time=262.996..2463.832 rows=575745 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                             Buffers: shared hit=218990 read=12263
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12141.70 rows=575978 width=0) (actual time=190.347..190.347 rows=578635 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                                   Buffers: shared read=1601
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..689355.82 rows=14916053 width=12) (actual time=0.107..13909.784 rows=14823274 loops=1)
                                       Buffers: shared hit=1093426 read=64480 dirtied=117
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2452.492..2452.492 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=145) (actual time=0.023..1070.629 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.028..0.028 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=0.009..0.018 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 29765.123 ms
(40 rows)

COMMIT;
COMMIT