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=923050.62..923051.12 rows=200 width=8) (actual time=67007.837..67007.838 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=275886 read=14182 written=484
   ->  HashAggregate  (cost=923040.98..923042.98 rows=200 width=8) (actual time=67007.722..67007.731 rows=44 loops=1)
         Buffers: shared hit=275883 read=14182 written=484
         ->  HashAggregate  (cost=885540.98..900540.98 rows=1500000 width=8) (actual time=65973.566..66687.707 rows=1500000 loops=1)
               Buffers: shared hit=275883 read=14182 written=484
               ->  Hash Right Join  (cost=69028.00..810920.54 rows=14924087 width=8) (actual time=1049.322..46662.607 rows=15352288 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=275883 read=14182 written=484
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14924087 width=8) (actual time=0.032..10300.143 rows=14852270 loops=1)
                           Filter: ((o_comment)::text !~~ '%pending%requests%'::text)
                           Rows Removed by Filter: 162730
                           Buffers: shared hit=240605 read=14182 written=484
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1047.385..1047.385 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=0.017..557.616 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 67047.203 ms
(21 rows)

COMMIT;
COMMIT