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%accounts%'
		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=850073.35..850073.85 rows=200 width=8) (actual time=45183.007..45183.010 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=235313 read=55009 written=368
   ->  HashAggregate  (cost=850063.71..850065.71 rows=200 width=8) (actual time=45182.906..45182.921 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=235310 read=55009 written=368
         ->  HashAggregate  (cost=812563.71..827563.71 rows=1500000 width=8) (actual time=43959.033..44863.842 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=235310 read=55009 written=368
               ->  Hash Right Join  (cost=69028.00..737642.99 rows=14984143 width=8) (actual time=1079.106..25998.768 rows=15353812 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=235310 read=55009 written=368
                     ->  Seq Scan on orders  (cost=0.00..443852.85 rows=14984143 width=8) (actual time=0.025..8343.072 rows=14853790 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161210
                           Buffers: shared hit=200035 read=55006 written=368
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1066.842..1066.842 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35275 read=3
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.018..565.218 rows=1500000 loops=1)
                                 Buffers: shared hit=35275 read=3
 Planning time: 2.802 ms
 Execution time: 45216.732 ms
(24 rows)

COMMIT;
COMMIT