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=1198003.32..1198003.37 rows=20 width=176) (actual time=35644.396..35644.405 rows=20 loops=1)
   Buffers: shared hit=1317934 read=112075 dirtied=173 written=9
   ->  Sort  (cost=1198003.32..1199439.23 rows=574363 width=176) (actual time=35644.390..35644.392 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=1317934 read=112075 dirtied=173 written=9
         ->  HashAggregate  (cost=1176976.10..1182719.73 rows=574363 width=176) (actual time=34850.446..35397.231 rows=381608 loops=1)
               Buffers: shared hit=1317931 read=112075 dirtied=173 written=9
               ->  Hash Join  (cost=402920.11..1162617.03 rows=574363 width=176) (actual time=8690.602..30574.090 rows=1147960 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1317931 read=112075 dirtied=173 written=9
                     ->  Hash Join  (cost=402918.55..1154717.97 rows=574363 width=154) (actual time=8690.545..29865.486 rows=1147960 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1317930 read=112075 dirtied=173 written=9
                           ->  Merge Join  (cost=333890.55..1074202.71 rows=574363 width=12) (actual time=3458.740..22102.967 rows=1147960 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1289182 read=105545 dirtied=173 written=9
                                 ->  Sort  (cost=333890.53..335345.13 rows=581841 width=8) (actual time=3458.598..3640.216 rows=574385 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51501kB
                                       Buffers: shared hit=172720 read=60111 dirtied=173
                                       ->  Bitmap Heap Scan on orders  (cost=12637.86..278178.48 rows=581841 width=8) (actual time=434.185..3174.905 rows=574385 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Buffers: shared hit=172720 read=60111 dirtied=173
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12492.40 rows=581841 width=0) (actual time=339.730..339.730 rows=581759 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1666
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..694123.30 rows=15014422 width=12) (actual time=0.069..15112.052 rows=14822461 loops=1)
                                       Buffers: shared hit=1116462 read=45434 written=9
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=5229.394..5229.394 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=28748 read=6530
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.015..1455.600 rows=1500000 loops=1)
                                       Buffers: shared hit=28748 read=6530
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.032..0.032 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..0.014 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 35707.529 ms
(40 rows)

COMMIT;
COMMIT