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=844156.68..844157.18 rows=200 width=8) (actual time=28264.590..28264.593 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=218124 read=70679 written=210
   ->  HashAggregate  (cost=844147.04..844149.04 rows=200 width=8) (actual time=28264.497..28264.503 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=218121 read=70679 written=210
         ->  HashAggregate  (cost=806647.04..821647.04 rows=1500000 width=8) (actual time=27449.976..27935.076 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=218121 read=70679 written=210
               ->  Hash Right Join  (cost=69028.00..732544.61 rows=14820487 width=8) (actual time=929.630..18388.822 rows=15338728 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=218121 read=70679 written=210
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14820487 width=8) (actual time=0.030..8099.741 rows=14838708 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%requests%'::text)
                           Rows Removed by Filter: 161292
                           Buffers: shared hit=182853 read=70669 written=209
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=921.875..921.875 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35268 read=10 written=1
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.015..502.331 rows=1500000 loops=1)
                                 Buffers: shared hit=35268 read=10 written=1
 Planning time: 2.831 ms
 Execution time: 28279.165 ms
(24 rows)

COMMIT;
COMMIT