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 '1993-03-01'
	and o_orderdate < cast(date '1993-03-01' + 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=1189161.59..1189161.64 rows=20 width=176) (actual time=23644.584..23644.590 rows=20 loops=1)
   Buffers: shared hit=1229078 read=203583 dirtied=2813 written=706
   ->  Sort  (cost=1189161.59..1190562.85 rows=560505 width=176) (actual time=23644.579..23644.581 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=1229078 read=203583 dirtied=2813 written=706
         ->  HashAggregate  (cost=1168641.70..1174246.75 rows=560505 width=176) (actual time=23113.037..23490.776 rows=382265 loops=1)
               Buffers: shared hit=1229075 read=203583 dirtied=2813 written=706
               ->  Hash Join  (cost=398828.57..1154629.08 rows=560505 width=176) (actual time=4676.395..20717.452 rows=1149306 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1229075 read=203583 dirtied=2813 written=706
                     ->  Hash Join  (cost=398827.01..1146920.57 rows=560505 width=154) (actual time=4676.356..20195.422 rows=1149306 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1229074 read=203583 dirtied=2813 written=706
                           ->  Merge Join  (cost=329799.01..1066682.47 rows=560505 width=12) (actual time=2091.659..15426.308 rows=1149306 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1193797 read=203582 dirtied=2813 written=706
                                 ->  Sort  (cost=329798.99..331213.87 rows=565953 width=8) (actual time=2091.433..2231.774 rows=573975 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51482kB
                                       Buffers: shared hit=229009 read=2222 dirtied=308
                                       ->  Bitmap Heap Scan on orders  (cost=12190.97..275721.27 rows=565953 width=8) (actual time=357.150..1888.782 rows=573975 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                             Buffers: shared hit=229009 read=2222 dirtied=308
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12049.48 rows=565953 width=0) (actual time=226.514..226.514 rows=577345 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                                   Buffers: shared hit=87 read=1545
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..691049.83 rows=14959539 width=12) (actual time=0.128..10943.365 rows=14822925 loops=1)
                                       Buffers: shared hit=964788 read=201360 dirtied=2505 written=706
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2582.627..2582.627 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35277 read=1
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.011..660.753 rows=1500000 loops=1)
                                       Buffers: shared hit=35277 read=1
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 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=0.005..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 23721.367 ms
(40 rows)

COMMIT;
COMMIT