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 '%pending%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=923939.98..923940.48 rows=200 width=8) (actual time=62327.721..62327.725 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=212666 read=77910 dirtied=1 written=12
   ->  HashAggregate  (cost=923930.34..923932.34 rows=200 width=8) (actual time=62327.590..62327.599 rows=44 loops=1)
         Buffers: shared hit=212663 read=77910 dirtied=1 written=12
         ->  HashAggregate  (cost=886430.34..901430.34 rows=1500000 width=8) (actual time=61126.029..61985.194 rows=1500000 loops=1)
               Buffers: shared hit=212663 read=77910 dirtied=1 written=12
               ->  Hash Right Join  (cost=69028.00..811808.85 rows=14924298 width=8) (actual time=1847.094..44435.671 rows=15352322 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=212663 read=77910 dirtied=1 written=12
                     ->  Seq Scan on orders  (cost=0.00..444294.89 rows=14924298 width=8) (actual time=0.046..10131.204 rows=14852304 loops=1)
                           Filter: ((o_comment)::text !~~ '%pending%requests%'::text)
                           Rows Removed by Filter: 162696
                           Buffers: shared hit=212661 read=42634 dirtied=1 written=10
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1845.116..1845.116 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276 written=2
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.021..1118.681 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=2
 Total runtime: 62358.627 ms
(21 rows)

COMMIT;
COMMIT