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%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=844890.78..844891.28 rows=200 width=8) (actual time=32431.069..32431.071 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=184334 read=104722 written=170
   ->  HashAggregate  (cost=844881.14..844883.14 rows=200 width=8) (actual time=32430.977..32430.990 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=184331 read=104722 written=170
         ->  HashAggregate  (cost=807381.14..822381.14 rows=1500000 width=8) (actual time=31458.787..32104.997 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=184331 read=104722 written=170
               ->  Hash Right Join  (cost=69028.00..733205.26 rows=14835177 width=8) (actual time=1312.859..20479.743 rows=15352872 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=184331 read=104722 written=170
                     ->  Seq Scan on orders  (cost=0.00..441649.60 rows=14835177 width=8) (actual time=0.031..8967.311 rows=14852854 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%deposits%'::text)
                           Rows Removed by Filter: 162146
                           Buffers: shared hit=184328 read=69447 written=5
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1299.999..1299.999 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=3 read=35275 written=165
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.012..827.164 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275 written=165
 Planning time: 3.612 ms
 Execution time: 32452.263 ms
(24 rows)

COMMIT;
COMMIT