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 '1993-10-01'
	and o_orderdate < cast(date '1993-10-01' + 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=1194008.68..1194008.73 rows=20 width=176) (actual time=51069.673..51069.680 rows=20 loops=1)
   Buffers: shared hit=475884 read=947436 dirtied=1408 written=26731
   ->  Sort  (cost=1194008.68..1195440.58 rows=572761 width=176) (actual time=51069.668..51069.672 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=475884 read=947436 dirtied=1408 written=26731
         ->  HashAggregate  (cost=1173040.10..1178767.71 rows=572761 width=176) (actual time=50573.601..50912.294 rows=381471 loops=1)
               Buffers: shared hit=475881 read=947436 dirtied=1408 written=26731
               ->  Hash Join  (cost=401628.85..1158721.08 rows=572761 width=176) (actual time=8537.395..46670.318 rows=1148508 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=475881 read=947436 dirtied=1408 written=26731
                     ->  Hash Join  (cost=401627.29..1150844.05 rows=572761 width=154) (actual time=8537.339..45891.178 rows=1148508 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=475880 read=947436 dirtied=1408 written=26731
                           ->  Merge Join  (cost=332599.29..1070360.83 rows=572761 width=12) (actual time=6017.406..40890.435 rows=1148508 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=440602 read=947436 dirtied=1408 written=26731
                                 ->  Sort  (cost=332599.27..334048.89 rows=579850 width=8) (actual time=6016.464..6227.492 rows=573887 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51477kB
                                       Buffers: shared hit=120851 read=111110 dirtied=226 written=10
                                       ->  Bitmap Heap Scan on orders  (cost=12593.45..277092.20 rows=579850 width=8) (actual time=370.370..5679.600 rows=573887 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                             Buffers: shared hit=120851 read=111110 dirtied=226 written=10
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12448.49 rows=579850 width=0) (actual time=294.648..294.648 rows=578953 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                                   Buffers: shared hit=1656 read=1
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..691722.85 rows=14964740 width=12) (actual time=0.922..31007.630 rows=14822772 loops=1)
                                       Buffers: shared hit=319751 read=836326 dirtied=1182 written=26721
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2517.488..2517.488 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..1208.393 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.029..0.029 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..0.016 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 51112.002 ms
(40 rows)

COMMIT;
COMMIT