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%packages%'
		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=843256.72..843257.22 rows=200 width=8) (actual time=34347.733..34347.735 rows=47 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=260026 read=28777
   ->  HashAggregate  (cost=843247.08..843249.08 rows=200 width=8) (actual time=34347.598..34347.606 rows=47 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=260023 read=28777
         ->  HashAggregate  (cost=805747.08..820747.08 rows=1500000 width=8) (actual time=33158.731..34060.487 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=260023 read=28777
               ->  Hash Right Join  (cost=69028.00..731869.64 rows=14775489 width=8) (actual time=1075.578..18465.992 rows=15352730 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=260023 read=28777
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14775489 width=8) (actual time=0.042..6794.533 rows=14852707 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162293
                           Buffers: shared hit=246912 read=6610
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1060.864..1060.864 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=13111 read=22167
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.028..515.589 rows=1500000 loops=1)
                                 Buffers: shared hit=13111 read=22167
 Planning time: 4.978 ms
 Execution time: 34367.109 ms
(24 rows)

COMMIT;
COMMIT