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 '1993-06-01'
	and o_orderdate < cast(date '1993-06-01' + 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=1184690.41..1184690.46 rows=20 width=175) (actual time=79609.993..79610.003 rows=20 loops=1)
   Buffers: shared hit=1134804 read=274761 dirtied=1066 written=8448
   ->  Sort  (cost=1184690.41..1186093.56 rows=561258 width=175) (actual time=79609.988..79609.993 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=1134804 read=274761 dirtied=1066 written=8448
         ->  HashAggregate  (cost=1164142.96..1169755.54 rows=561258 width=175) (actual time=79021.010..79432.245 rows=381529 loops=1)
               Buffers: shared hit=1134801 read=274761 dirtied=1066 written=8448
               ->  Hash Join  (cost=397410.47..1150111.51 rows=561258 width=175) (actual time=11188.365..74864.654 rows=1147540 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1134801 read=274761 dirtied=1066 written=8448
                     ->  Hash Join  (cost=397408.91..1142392.65 rows=561258 width=153) (actual time=11188.319..73903.381 rows=1147540 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1134800 read=274761 dirtied=1066 written=8448
                           ->  Merge Join  (cost=328380.91..1062139.49 rows=561258 width=12) (actual time=7234.530..66565.618 rows=1147540 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1099522 read=274761 dirtied=1066 written=8448
                                 ->  Sort  (cost=328380.90..329796.49 rows=566234 width=8) (actual time=7234.331..7460.454 rows=574297 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51497kB
                                       Buffers: shared hit=226609 read=3385
                                       ->  Bitmap Heap Scan on orders  (cost=12005.79..274274.30 rows=566234 width=8) (actual time=614.070..6924.506 rows=574297 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Buffers: shared hit=226609 read=3385
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11864.24 rows=566234 width=0) (actual time=465.199..465.199 rows=574834 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1571
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..688071.83 rows=14897883 width=12) (actual time=0.135..55296.912 rows=14823287 loops=1)
                                       Buffers: shared hit=872913 read=271376 dirtied=1066 written=8448
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3951.304..3951.304 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=0.036..1742.117 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 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..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 79708.037 ms
(40 rows)

COMMIT;
COMMIT