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%requests%'
		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=921438.22..921438.72 rows=200 width=8) (actual time=89293.818..89293.821 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=271574 read=17988
   ->  HashAggregate  (cost=921428.57..921430.57 rows=200 width=8) (actual time=89293.704..89293.713 rows=46 loops=1)
         Buffers: shared hit=271571 read=17988
         ->  HashAggregate  (cost=883928.57..898928.57 rows=1500000 width=8) (actual time=88038.161..88932.594 rows=1500000 loops=1)
               Buffers: shared hit=271571 read=17988
               ->  Hash Right Join  (cost=69028.00..809454.50 rows=14894815 width=8) (actual time=2445.611..64014.130 rows=15353523 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=271571 read=17988
                     ->  Seq Scan on orders  (cost=0.00..442530.20 rows=14894815 width=8) (actual time=0.050..20538.144 rows=14853505 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%requests%'::text)
                           Rows Removed by Filter: 161495
                           Buffers: shared hit=236293 read=17988
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2443.599..2443.599 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.015..1638.072 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 89328.540 ms
(21 rows)

COMMIT;
COMMIT