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=927880.83..927881.33 rows=200 width=8) (actual time=69579.397..69579.399 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=263143 read=28192 written=11
   ->  HashAggregate  (cost=927871.19..927873.19 rows=200 width=8) (actual time=69579.271..69579.283 rows=45 loops=1)
         Buffers: shared hit=263140 read=28192 written=11
         ->  HashAggregate  (cost=890371.19..905371.19 rows=1500000 width=8) (actual time=68330.958..69256.785 rows=1500000 loops=1)
               Buffers: shared hit=263140 read=28192 written=11
               ->  Hash Right Join  (cost=69028.00..815225.71 rows=15029096 width=8) (actual time=1477.610..50147.106 rows=15354058 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=263140 read=28192 written=11
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=15029096 width=8) (actual time=0.041..12695.013 rows=14854042 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 160958
                           Buffers: shared hit=227863 read=28191 written=11
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1474.951..1474.951 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35277 read=1
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..803.256 rows=1500000 loops=1)
                                 Buffers: shared hit=35277 read=1
 Total runtime: 69611.804 ms
(21 rows)

COMMIT;
COMMIT