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%requests%'
		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=844456.96..844457.46 rows=200 width=8) (actual time=32780.188..32780.194 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=228814 read=59989 written=1907
   ->  HashAggregate  (cost=844447.32..844449.32 rows=200 width=8) (actual time=32780.060..32780.066 rows=44 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=228811 read=59989 written=1907
         ->  HashAggregate  (cost=806947.32..821947.32 rows=1500000 width=8) (actual time=31764.380..32471.367 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=228811 read=59989 written=1907
               ->  Hash Right Join  (cost=69028.00..732769.82 rows=14835501 width=8) (actual time=1039.690..18794.166 rows=15338525 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=228811 read=59989 written=1907
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14835501 width=8) (actual time=0.031..8515.822 rows=14838502 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%requests%'::text)
                           Rows Removed by Filter: 161498
                           Buffers: shared hit=207463 read=46059 written=792
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1024.209..1024.209 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=21348 read=13930 written=1115
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.009..585.009 rows=1500000 loops=1)
                                 Buffers: shared hit=21348 read=13930 written=1115
 Planning time: 2.786 ms
 Execution time: 32873.655 ms
(24 rows)

COMMIT;
COMMIT