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 '1993-02-01'
	and o_orderdate < cast(date '1993-02-01' + 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=1158238.06..1158238.11 rows=20 width=175) (actual time=26678.623..26678.629 rows=20 loops=1)
   Buffers: shared hit=794309 read=628597 written=8822
   ->  Sort  (cost=1158238.06..1159643.40 rows=562137 width=175) (actual time=26678.620..26678.622 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=794309 read=628597 written=8822
         ->  HashAggregate  (cost=1137658.42..1143279.79 rows=562137 width=175) (actual time=26260.002..26533.801 rows=372881 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=794306 read=628597 written=8822
               ->  Hash Join  (cost=353389.31..1123605.00 rows=562137 width=175) (actual time=4251.806..23138.779 rows=1113926 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=794306 read=628597 written=8822
                     ->  Hash Join  (cost=353387.75..1115874.05 rows=562137 width=153) (actual time=4251.761..22729.184 rows=1113926 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=794305 read=628597 written=8822
                           ->  Hash Join  (cost=284359.75..1038414.00 rows=562137 width=12) (actual time=2464.705..20154.901 rows=1113926 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=794303 read=593321 written=8782
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..692289.57 rows=14971665 width=12) (actual time=0.062..13976.443 rows=14822519 loops=1)
                                       Buffers: shared hit=617367 read=539683 written=8736
                                 ->  Hash  (cost=277234.85..277234.85 rows=569957 width=8) (actual time=2460.499..2460.499 rows=555745 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 29901kB
                                       Buffers: shared hit=176936 read=53638 written=46
                                       ->  Bitmap Heap Scan on orders  (cost=12378.49..277234.85 rows=569957 width=8) (actual time=290.532..2266.628 rows=555745 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                             Heap Blocks: exact=228964
                                             Buffers: shared hit=176936 read=53638 written=46
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12236.00 rows=569957 width=0) (actual time=211.012..211.012 rows=561765 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                                   Buffers: shared read=1610 written=2
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1777.997..1777.997 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=40
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.008..924.408 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=40
                     ->  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=0.007..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.159 ms
 Execution time: 26700.659 ms
(42 rows)

COMMIT;
COMMIT