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=927921.76..927922.26 rows=200 width=8) (actual time=66095.961..66095.963 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=289478 read=2110 dirtied=1 written=737
   ->  HashAggregate  (cost=927912.11..927914.11 rows=200 width=8) (actual time=66095.865..66095.875 rows=46 loops=1)
         Buffers: shared hit=289475 read=2110 dirtied=1 written=737
         ->  HashAggregate  (cost=890412.11..905412.11 rows=1500000 width=8) (actual time=64957.143..65739.079 rows=1500000 loops=1)
               Buffers: shared hit=289475 read=2110 dirtied=1 written=737
               ->  Hash Right Join  (cost=69028.00..815346.51 rows=15013121 width=8) (actual time=1402.640..47030.431 rows=15352345 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=289475 read=2110 dirtied=1 written=737
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15013121 width=8) (actual time=0.045..11057.473 rows=14852327 loops=1)
                           Filter: ((o_comment)::text !~~ '%pending%requests%'::text)
                           Rows Removed by Filter: 162673
                           Buffers: shared hit=254197 read=2110 dirtied=1 written=737
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1400.506..1400.506 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.014..750.196 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 66122.477 ms
(21 rows)

COMMIT;
COMMIT