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=918320.37..918320.87 rows=200 width=8) (actual time=97387.396..97387.398 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=181334 read=107722
   ->  HashAggregate  (cost=918310.72..918312.72 rows=200 width=8) (actual time=97387.299..97387.309 rows=46 loops=1)
         Buffers: shared hit=181331 read=107722
         ->  HashAggregate  (cost=880810.72..895810.72 rows=1500000 width=8) (actual time=96252.514..97030.165 rows=1500000 loops=1)
               Buffers: shared hit=181331 read=107722
               ->  Hash Right Join  (cost=69028.00..806784.10 rows=14805325 width=8) (actual time=2611.021..72202.180 rows=15353957 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=181331 read=107722
                     ->  Seq Scan on orders  (cost=0.00..441649.60 rows=14805325 width=8) (actual time=0.050..24217.470 rows=14853941 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 161059
                           Buffers: shared hit=151020 read=102755
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2609.181..2609.181 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=30311 read=4967
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.012..1567.943 rows=1500000 loops=1)
                                 Buffers: shared hit=30311 read=4967
 Total runtime: 97430.995 ms
(21 rows)

COMMIT;
COMMIT