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 '1993-08-01'
	and o_orderdate < cast(date '1993-08-01' + 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=1157887.87..1157887.92 rows=20 width=175) (actual time=23604.303..23604.311 rows=20 loops=1)
   Buffers: shared hit=849804 read=571871 written=1380
   ->  Sort  (cost=1157887.87..1159321.53 rows=573463 width=175) (actual time=23604.300..23604.303 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=849804 read=571871 written=1380
         ->  HashAggregate  (cost=1136893.59..1142628.22 rows=573463 width=175) (actual time=23205.982..23462.604 rows=381922 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=849801 read=571871 written=1380
               ->  Hash Join  (cost=352813.78..1122557.02 rows=573463 width=175) (actual time=3967.926..21032.363 rows=1147536 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=849801 read=571871 written=1380
                     ->  Hash Join  (cost=352812.22..1114670.34 rows=573463 width=153) (actual time=3967.891..20648.169 rows=1147536 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=849800 read=571871 written=1380
                           ->  Hash Join  (cost=283784.22..1037040.40 rows=573463 width=12) (actual time=2168.220..18060.061 rows=1147536 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=846725 read=539668 written=1333
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691403.00 rows=14965061 width=12) (actual time=0.074..12492.761 rows=14823054 loops=1)
                                       Buffers: shared hit=651625 read=503395 written=1295
                                 ->  Hash  (cost=276541.28..276541.28 rows=579400 width=8) (actual time=2161.534..2161.534 rows=574386 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30629kB
                                       Buffers: shared hit=195100 read=36273 written=38
                                       ->  Bitmap Heap Scan on orders  (cost=12555.28..276541.28 rows=579400 width=8) (actual time=288.778..1974.364 rows=574386 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                             Heap Blocks: exact=229729
                                             Buffers: shared hit=195100 read=36273 written=38
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12410.43 rows=579400 width=0) (actual time=209.667..209.667 rows=578247 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                                   Buffers: shared read=1644
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1784.131..1784.131 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=3075 read=32203 written=47
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..862.046 rows=1500000 loops=1)
                                       Buffers: shared hit=3075 read=32203 written=47
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.022..0.022 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..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.273 ms
 Execution time: 23630.535 ms
(42 rows)

COMMIT;
COMMIT