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 '%special%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=921557.57..921558.07 rows=200 width=8) (actual time=86355.823..86355.827 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=278494 read=11574 written=1
   ->  HashAggregate  (cost=921547.92..921549.92 rows=200 width=8) (actual time=86355.713..86355.724 rows=46 loops=1)
         Buffers: shared hit=278491 read=11574 written=1
         ->  HashAggregate  (cost=884047.92..899047.92 rows=1500000 width=8) (actual time=85039.812..85996.272 rows=1500000 loops=1)
               Buffers: shared hit=278491 read=11574 written=1
               ->  Hash Right Join  (cost=69028.00..809726.10 rows=14864365 width=8) (actual time=1880.871..62436.508 rows=15353984 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=278491 read=11574 written=1
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14864365 width=8) (actual time=0.039..20491.920 rows=14853968 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 161032
                           Buffers: shared hit=243352 read=11435 written=1
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1879.179..1879.179 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35139 read=139
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.010..802.499 rows=1500000 loops=1)
                                 Buffers: shared hit=35139 read=139
 Total runtime: 86398.547 ms
(21 rows)

COMMIT;
COMMIT