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=847394.66..847395.16 rows=200 width=8) (actual time=25690.476..25690.479 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=223026 read=66789 written=54
   ->  HashAggregate  (cost=847385.02..847387.02 rows=200 width=8) (actual time=25690.379..25690.388 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=223023 read=66789 written=54
         ->  HashAggregate  (cost=809885.02..824885.02 rows=1500000 width=8) (actual time=24964.645..25401.410 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=223023 read=66789 written=54
               ->  Hash Right Join  (cost=69028.00..735413.39 rows=14894326 width=8) (actual time=920.552..16494.811 rows=15337937 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=223023 read=66789 written=54
                     ->  Seq Scan on orders  (cost=0.00..442970.50 rows=14894326 width=8) (actual time=0.034..7348.540 rows=14837916 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162084
                           Buffers: shared hit=193923 read=60611 written=54
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=909.222..909.222 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=29100 read=6178
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..519.571 rows=1500000 loops=1)
                                 Buffers: shared hit=29100 read=6178
 Planning time: 2.614 ms
 Execution time: 25741.361 ms
(24 rows)

COMMIT;
COMMIT