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 '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + 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=1155492.04..1155492.09 rows=20 width=175) (actual time=28089.044..28089.051 rows=20 loops=1)
   Buffers: shared hit=659503 read=757040 dirtied=613 written=9353
   ->  Sort  (cost=1155492.04..1156922.02 rows=571992 width=175) (actual time=28089.041..28089.046 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=659503 read=757040 dirtied=613 written=9353
         ->  HashAggregate  (cost=1134551.62..1140271.54 rows=571992 width=175) (actual time=27569.549..27935.027 rows=381577 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=659500 read=757040 dirtied=613 written=9353
               ->  Hash Join  (cost=352037.35..1120251.82 rows=571992 width=175) (actual time=3735.897..25393.530 rows=1148270 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=659500 read=757040 dirtied=613 written=9353
                     ->  Hash Join  (cost=352035.78..1112385.36 rows=571992 width=153) (actual time=3735.861..24994.100 rows=1148270 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=659499 read=757040 dirtied=613 written=9353
                           ->  Hash Join  (cost=283007.78..1034777.48 rows=571992 width=12) (actual time=2083.109..22164.304 rows=1148270 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=654564 read=726697 dirtied=613 written=9353
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690042.02 rows=14935519 width=12) (actual time=0.056..14846.069 rows=14823276 loops=1)
                                       Buffers: shared hit=466482 read=683687 dirtied=507 written=9279
                                 ->  Hash  (cost=275783.54..275783.54 rows=577905 width=8) (actual time=2078.830..2078.830 rows=574115 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30619kB
                                       Buffers: shared hit=188082 read=43010 dirtied=106 written=74
                                       ->  Bitmap Heap Scan on orders  (cost=12327.96..275783.54 rows=577905 width=8) (actual time=261.526..1897.581 rows=574115 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=229498
                                             Buffers: shared hit=188082 read=43010 dirtied=106 written=74
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12183.48 rows=577905 width=0) (actual time=187.195..187.195 rows=576951 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared read=1594
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1645.430..1645.430 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=4935 read=30343
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.013..815.411 rows=1500000 loops=1)
                                       Buffers: shared hit=4935 read=30343
                     ->  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: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.007 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.845 ms
 Execution time: 28107.106 ms
(42 rows)

COMMIT;
COMMIT