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 '1994-06-01'
	and o_orderdate < cast(date '1994-06-01' + 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=1191765.37..1191765.42 rows=20 width=175) (actual time=60880.447..60880.454 rows=20 loops=1)
   Buffers: shared hit=1260020 read=163462 written=3565
   ->  Sort  (cost=1191765.37..1193209.92 rows=577817 width=175) (actual time=60880.443..60880.447 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=1260020 read=163462 written=3565
         ->  HashAggregate  (cost=1170611.70..1176389.87 rows=577817 width=175) (actual time=60352.112..60719.547 rows=382131 loops=1)
               Buffers: shared hit=1260017 read=163462 written=3565
               ->  Hash Join  (cost=400489.79..1156166.28 rows=577817 width=175) (actual time=10541.097..55575.289 rows=1149840 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1260017 read=163462 written=3565
                     ->  Hash Join  (cost=400488.23..1148219.73 rows=577817 width=153) (actual time=10540.866..54633.290 rows=1149840 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1260016 read=163462 written=3565
                           ->  Merge Join  (cost=331460.23..1067635.39 rows=577817 width=12) (actual time=7455.327..49001.114 rows=1149840 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1224738 read=163462 written=3565
                                 ->  Sort  (cost=331460.22..332917.57 rows=582939 width=8) (actual time=7455.208..7668.325 rows=574847 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51522kB
                                       Buffers: shared hit=227949 read=2839
                                       ->  Bitmap Heap Scan on orders  (cost=12357.02..275635.11 rows=582939 width=8) (actual time=653.059..7148.850 rows=574847 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                             Buffers: shared hit=227949 read=2839
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12211.29 rows=582939 width=0) (actual time=556.107..556.107 rows=577200 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                                   Buffers: shared hit=2 read=1577
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690127.87 rows=14942456 width=12) (actual time=0.100..37582.554 rows=14823475 loops=1)
                                       Buffers: shared hit=996789 read=160623 written=3565
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3083.902..3083.902 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=0.012..1728.615 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.217..0.217 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=0.201..0.208 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 60940.192 ms
(40 rows)

COMMIT;
COMMIT