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=927990.23..927990.73 rows=200 width=8) (actual time=62914.040..62914.040 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=251678 read=40163 written=6
   ->  HashAggregate  (cost=927980.59..927982.59 rows=200 width=8) (actual time=62913.919..62913.929 rows=45 loops=1)
         Buffers: shared hit=251675 read=40163 written=6
         ->  HashAggregate  (cost=890480.59..905480.59 rows=1500000 width=8) (actual time=61601.401..62575.135 rows=1500000 loops=1)
               Buffers: shared hit=251675 read=40163 written=6
               ->  Hash Right Join  (cost=69028.00..815489.35 rows=14998248 width=8) (actual time=1874.261..44912.329 rows=15352333 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=251675 read=40163 written=6
                     ->  Seq Scan on orders  (cost=0.00..446496.39 rows=14998248 width=8) (actual time=0.050..9340.496 rows=14852315 loops=1)
                           Filter: ((o_comment)::text !~~ '%pending%requests%'::text)
                           Rows Removed by Filter: 162685
                           Buffers: shared hit=251673 read=4887 written=6
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1871.701..1871.701 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.006..1073.567 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276
 Total runtime: 62967.701 ms
(21 rows)

COMMIT;
COMMIT