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=850074.61..850075.11 rows=200 width=8) (actual time=40294.927..40294.932 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=252644 read=37678 written=31
   ->  HashAggregate  (cost=850064.97..850066.97 rows=200 width=8) (actual time=40294.832..40294.839 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=252641 read=37678 written=31
         ->  HashAggregate  (cost=812564.97..827564.97 rows=1500000 width=8) (actual time=39387.328..39985.664 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=252641 read=37678 written=31
               ->  Hash Right Join  (cost=69028.00..737643.94 rows=14984206 width=8) (actual time=1150.172..23918.353 rows=15353544 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=252641 read=37678 written=31
                     ->  Seq Scan on orders  (cost=0.00..443852.85 rows=14984206 width=8) (actual time=0.029..7537.843 rows=14853526 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%requests%'::text)
                           Rows Removed by Filter: 161474
                           Buffers: shared hit=252639 read=2402
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1138.609..1138.609 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276 written=31
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.010..718.864 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=31
 Planning time: 3.133 ms
 Execution time: 40321.680 ms
(24 rows)

COMMIT;
COMMIT