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=851688.19..851688.69 rows=200 width=8) (actual time=40425.925..40425.927 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=187158 read=103924 written=1348
   ->  HashAggregate  (cost=851678.55..851680.55 rows=200 width=8) (actual time=40425.803..40425.817 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=187155 read=103924 written=1348
         ->  HashAggregate  (cost=814178.55..829178.55 rows=1500000 width=8) (actual time=39451.248..40098.529 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=187155 read=103924 written=1348
               ->  Hash Right Join  (cost=69028.00..739184.78 rows=14998753 width=8) (actual time=1232.468..22723.037 rows=15352726 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=187155 read=103924 written=1348
                     ->  Seq Scan on orders  (cost=0.00..445175.49 rows=14998753 width=8) (actual time=0.028..8822.367 rows=14852705 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162295
                           Buffers: shared hit=176659 read=79142 written=1339
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1219.008..1219.008 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=10496 read=24782 written=9
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.018..689.793 rows=1500000 loops=1)
                                 Buffers: shared hit=10496 read=24782 written=9
 Planning time: 3.499 ms
 Execution time: 40458.428 ms
(24 rows)

COMMIT;
COMMIT