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=1152304.19..1152304.24 rows=20 width=175) (actual time=29914.621..29914.628 rows=20 loops=1)
   Buffers: shared hit=717576 read=705437 written=8549
   ->  Sort  (cost=1152304.19..1153713.57 rows=563751 width=175) (actual time=29914.618..29914.621 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=717576 read=705437 written=8549
         ->  HashAggregate  (cost=1131665.47..1137302.98 rows=563751 width=175) (actual time=29338.395..29745.205 rows=381230 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=717573 read=705437 written=8549
               ->  Hash Join  (cost=351726.99..1117571.69 rows=563751 width=175) (actual time=5406.378..27161.463 rows=1146458 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=717573 read=705437 written=8549
                     ->  Hash Join  (cost=351725.43..1109818.55 rows=563751 width=153) (actual time=5406.325..26718.734 rows=1146458 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=717572 read=705437 written=8549
                           ->  Hash Join  (cost=282697.43..1032334.29 rows=563751 width=12) (actual time=3100.825..23409.655 rows=1146458 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=690100 read=697631 written=8549
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688188.78 rows=14882934 width=12) (actual time=0.061..15738.709 rows=14808418 loops=1)
                                       Buffers: shared hit=556872 read=599933 written=3905
                                 ->  Hash  (cost=275552.11..275552.11 rows=571591 width=8) (actual time=3096.700..3096.700 rows=573680 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30602kB
                                       Buffers: shared hit=133228 read=97698 written=4644
                                       ->  Bitmap Heap Scan on orders  (cost=12191.24..275552.11 rows=571591 width=8) (actual time=296.080..2871.879 rows=573680 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Heap Blocks: exact=229332
                                             Buffers: shared hit=133228 read=97698 written=4644
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12048.34 rows=571591 width=0) (actual time=216.451..216.451 rows=577112 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1594
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2284.452..2284.452 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=27472 read=7806
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..1031.146 rows=1500000 loops=1)
                                       Buffers: shared hit=27472 read=7806
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.028..0.028 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=0.008..0.018 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 7.989 ms
 Execution time: 29936.260 ms
(42 rows)

COMMIT;
COMMIT