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 '1993-03-01'
	and o_orderdate < cast(date '1993-03-01' + 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=1185862.91..1185862.96 rows=20 width=175) (actual time=73928.183..73928.191 rows=20 loops=1)
   Buffers: shared hit=548698 read=875240 dirtied=826 written=3267
   ->  Sort  (cost=1185862.91..1187293.44 rows=572214 width=175) (actual time=73928.179..73928.184 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=548698 read=875240 dirtied=826 written=3267
         ->  HashAggregate  (cost=1164914.36..1170636.50 rows=572214 width=175) (actual time=73314.683..73734.443 rows=382012 loops=1)
               Buffers: shared hit=548695 read=875240 dirtied=826 written=3267
               ->  Hash Join  (cost=400487.49..1150609.01 rows=572214 width=175) (actual time=12596.927..68533.723 rows=1148303 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=548695 read=875240 dirtied=826 written=3267
                     ->  Hash Join  (cost=400485.93..1142739.50 rows=572214 width=153) (actual time=12596.875..67614.165 rows=1148303 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=548694 read=875240 dirtied=826 written=3267
                           ->  Merge Join  (cost=331457.93..1062267.22 rows=572214 width=12) (actual time=7644.673..59956.494 rows=1148303 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=548691 read=839965 dirtied=826 written=1586
                                 ->  Sort  (cost=331457.91..332915.21 rows=582921 width=8) (actual time=7644.511..7869.867 rows=573431 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51456kB
                                       Buffers: shared hit=189238 read=41512 written=1324
                                       ->  Bitmap Heap Scan on orders  (cost=12356.84..275634.66 rows=582921 width=8) (actual time=648.380..7305.394 rows=573431 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                             Buffers: shared hit=189238 read=41512 written=1324
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12211.11 rows=582921 width=0) (actual time=548.797..548.797 rows=576784 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                                   Buffers: shared hit=154 read=1446 written=60
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..685177.49 rows=14798034 width=12) (actual time=0.102..48336.214 rows=14808709 loops=1)
                                       Buffers: shared hit=359453 read=798453 dirtied=826 written=262
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=4950.046..4950.046 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=3 read=35275 written=1681
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..3501.338 rows=1500000 loops=1)
                                       Buffers: shared hit=3 read=35275 written=1681
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.024..0.024 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.009..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 73979.031 ms
(40 rows)

COMMIT;
COMMIT