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=843254.22..843254.72 rows=200 width=8) (actual time=31883.515..31883.518 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=196521 read=92282 written=559
   ->  HashAggregate  (cost=843244.58..843246.58 rows=200 width=8) (actual time=31883.416..31883.424 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=196518 read=92282 written=559
         ->  HashAggregate  (cost=805744.58..820744.58 rows=1500000 width=8) (actual time=31060.264..31566.059 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=196518 read=92282 written=559
               ->  Hash Right Join  (cost=69028.00..731867.76 rows=14775364 width=8) (actual time=1031.889..20609.007 rows=15338914 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=196518 read=92282 written=559
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14775364 width=8) (actual time=0.029..8388.380 rows=14838890 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161110
                           Buffers: shared hit=163205 read=90317 written=440
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1016.328..1016.328 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=33313 read=1965 written=119
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.018..525.345 rows=1500000 loops=1)
                                 Buffers: shared hit=33313 read=1965 written=119
 Planning time: 2.796 ms
 Execution time: 31910.739 ms
(24 rows)

COMMIT;
COMMIT