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 '1993-12-01'
	and o_orderdate < cast(date '1993-12-01' + 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=1155197.70..1155197.75 rows=20 width=175) (actual time=28836.626..28836.632 rows=20 loops=1)
   Buffers: shared hit=1013435 read=406244 dirtied=1378 written=1186
   ->  Sort  (cost=1155197.70..1156604.31 rows=562643 width=175) (actual time=28836.622..28836.624 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=1013435 read=406244 dirtied=1378 written=1186
         ->  HashAggregate  (cost=1134599.55..1140225.98 rows=562643 width=175) (actual time=28370.225..28687.516 rows=374994 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=1013432 read=406244 dirtied=1378 written=1186
               ->  Hash Join  (cost=351946.99..1120533.47 rows=562643 width=175) (actual time=3702.404..22772.515 rows=1121372 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1013432 read=406244 dirtied=1378 written=1186
                     ->  Hash Join  (cost=351945.42..1112795.57 rows=562643 width=153) (actual time=3702.368..22390.981 rows=1121372 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1013431 read=406244 dirtied=1378 written=1186
                           ->  Hash Join  (cost=282917.42..1035327.92 rows=562643 width=12) (actual time=2032.402..19741.272 rows=1121372 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1013429 read=370968 dirtied=1378 written=1186
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690721.02 rows=14950262 width=12) (actual time=0.061..13080.499 rows=14822937 loops=1)
                                       Buffers: shared hit=814083 read=340467 dirtied=1156 written=1186
                                 ->  Hash  (cost=275811.18..275811.18 rows=568465 width=8) (actual time=2027.271..2027.271 rows=561000 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30107kB
                                       Buffers: shared hit=199346 read=30501 dirtied=222
                                       ->  Bitmap Heap Scan on orders  (cost=12243.20..275811.18 rows=568465 width=8) (actual time=265.960..1852.910 rows=561000 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-12-01'::date) AND (o_orderdate < '1994-03-01'::date))
                                             Heap Blocks: exact=228253
                                             Buffers: shared hit=199346 read=30501 dirtied=222
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12101.09 rows=568465 width=0) (actual time=190.971..190.971 rows=564381 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-12-01'::date) AND (o_orderdate < '1994-03-01'::date))
                                                   Buffers: shared read=1594
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1659.313..1659.313 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.017..838.543 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  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: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.006..0.008 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.333 ms
 Execution time: 28865.629 ms
(42 rows)

COMMIT;
COMMIT