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 '%express%deposits%'
		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=849448.69..849449.19 rows=200 width=8) (actual time=30549.945..30549.947 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=248845 read=41984 written=35
   ->  HashAggregate  (cost=849439.05..849441.05 rows=200 width=8) (actual time=30549.825..30549.837 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=248842 read=41984 written=35
         ->  HashAggregate  (cost=811939.05..826939.05 rows=1500000 width=8) (actual time=29657.953..30219.415 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=248842 read=41984 written=35
               ->  Hash Right Join  (cost=69028.00..737395.08 rows=14908793 width=8) (actual time=996.690..19702.096 rows=15354647 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=248842 read=41984 written=35
                     ->  Seq Scan on orders  (cost=0.00..444735.19 rows=14908793 width=8) (actual time=0.031..9063.317 rows=14854629 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%deposits%'::text)
                           Rows Removed by Filter: 160371
                           Buffers: shared hit=213564 read=41984 written=35
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=985.103..985.103 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.017..563.952 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 3.099 ms
 Execution time: 31152.011 ms
(24 rows)

COMMIT;
COMMIT