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 '1993-08-01'
	and o_orderdate < cast(date '1993-08-01' + 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=1192702.33..1192702.38 rows=20 width=175) (actual time=39272.069..39272.078 rows=20 loops=1)
   Buffers: shared hit=378893 read=1045034 written=77458
   ->  Sort  (cost=1192702.33..1194119.34 rows=566804 width=175) (actual time=39272.063..39272.069 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=378893 read=1045034 written=77458
         ->  HashAggregate  (cost=1171951.84..1177619.88 rows=566804 width=175) (actual time=38718.534..39099.113 rows=381864 loops=1)
               Buffers: shared hit=378890 read=1045034 written=77458
               ->  Hash Join  (cost=401180.55..1157781.74 rows=566804 width=175) (actual time=4787.791..34903.682 rows=1147521 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=378890 read=1045034 written=77458
                     ->  Hash Join  (cost=401178.99..1149986.62 rows=566804 width=153) (actual time=4787.746..34123.709 rows=1147521 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=378889 read=1045034 written=77458
                           ->  Merge Join  (cost=332150.99..1069622.54 rows=566804 width=12) (actual time=2566.670..29605.716 rows=1147521 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=343611 read=1045034 written=77458
                                 ->  Sort  (cost=332143.43..333580.32 rows=574756 width=8) (actual time=2566.500..2759.458 rows=574383 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51501kB
                                       Buffers: shared hit=230404 read=1660
                                       ->  Bitmap Heap Scan on orders  (cost=12485.24..277160.58 rows=574756 width=8) (actual time=465.493..2332.699 rows=574383 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                             Buffers: shared hit=230404 read=1660
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12341.55 rows=574756 width=0) (actual time=296.608..296.608 rows=579920 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                                   Buffers: shared hit=2 read=1659
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..691549.51 rows=14955120 width=12) (actual time=0.144..23346.087 rows=14822650 loops=1)
                                       Buffers: shared hit=113207 read=1043374 written=77458
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2219.052..2219.052 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=0.018..992.925 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..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 39310.707 ms
(40 rows)

COMMIT;
COMMIT