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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1195521.59..1195521.64 rows=20 width=175) (actual time=95502.591..95502.597 rows=20 loops=1)
   Buffers: shared hit=733063 read=694928 dirtied=1038 written=19682
   ->  Sort  (cost=1195521.59..1196932.48 rows=564356 width=175) (actual time=95502.587..95502.589 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=733063 read=694928 dirtied=1038 written=19682
         ->  HashAggregate  (cost=1174860.72..1180504.28 rows=564356 width=175) (actual time=94907.868..95329.759 rows=378879 loops=1)
               Buffers: shared hit=733060 read=694928 dirtied=1038 written=19682
               ->  Hash Join  (cost=400671.33..1160751.82 rows=564356 width=175) (actual time=11705.912..90233.237 rows=1136398 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=733060 read=694928 dirtied=1038 written=19682
                     ->  Hash Join  (cost=400669.76..1152990.36 rows=564356 width=153) (actual time=11705.860..89235.813 rows=1136398 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=733059 read=694928 dirtied=1038 written=19682
                           ->  Merge Join  (cost=331641.76..1072675.24 rows=564356 width=12) (actual time=8251.622..82935.802 rows=1136398 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=697781 read=694928 dirtied=1038 written=19682
                                 ->  Sort  (cost=331641.76..333065.17 rows=569364 width=8) (actual time=8251.424..8523.362 rows=568003 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51202kB
                                       Buffers: shared hit=229100 read=2690
                                       ->  Bitmap Heap Scan on orders  (cost=12365.97..277213.43 rows=569364 width=8) (actual time=604.416..7385.390 rows=568003 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Buffers: shared hit=229100 read=2690
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12223.63 rows=569364 width=0) (actual time=512.280..512.280 rows=574112 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared hit=2 read=1642
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..694928.82 rows=15046395 width=12) (actual time=0.172..70415.536 rows=14822519 loops=1)
                                       Buffers: shared hit=468681 read=692238 dirtied=1038 written=19682
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3452.027..3452.027 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=0.016..1987.879 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: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.008..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 95559.480 ms
(40 rows)

COMMIT;
COMMIT