BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_count,
	count(*) as custdist
from
	(
		select
			c_custkey,
			count(o_orderkey)
		from
			customer left outer join orders on
				c_custkey = o_custkey
				and o_comment not like '%unusual%packages%'
		group by
			c_custkey
	) as c_orders (c_custkey, c_count)
group by
	c_count
order by
	custdist desc,
	c_count desc;
                                                                    QUERY PLAN                                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=847670.85..847671.35 rows=200 width=8) (actual time=38783.372..38783.375 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=242791 read=47531 written=1506
   ->  HashAggregate  (cost=847661.21..847663.21 rows=200 width=8) (actual time=38783.259..38783.267 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=242788 read=47531 written=1506
         ->  HashAggregate  (cost=810161.21..825161.21 rows=1500000 width=8) (actual time=37843.497..38474.906 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=242788 read=47531 written=1506
               ->  Hash Right Join  (cost=69028.00..735841.12 rows=14864018 width=8) (actual time=986.941..23947.439 rows=15352721 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=242788 read=47531 written=1506
                     ->  Seq Scan on orders  (cost=0.00..443852.85 rows=14864018 width=8) (actual time=0.029..7754.378 rows=14852700 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162300
                           Buffers: shared hit=207510 read=47531 written=1506
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=972.522..972.522 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..494.924 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.605 ms
 Execution time: 38807.848 ms
(24 rows)

COMMIT;
COMMIT