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=923063.09..923063.59 rows=200 width=8) (actual time=63431.392..63431.396 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=280211 read=9857 written=7
   ->  HashAggregate  (cost=923053.45..923055.45 rows=200 width=8) (actual time=63431.275..63431.281 rows=44 loops=1)
         Buffers: shared hit=280208 read=9857 written=7
         ->  HashAggregate  (cost=885553.45..900553.45 rows=1500000 width=8) (actual time=62301.709..63114.008 rows=1500000 loops=1)
               Buffers: shared hit=280208 read=9857 written=7
               ->  Hash Right Join  (cost=69028.00..810930.52 rows=14924586 width=8) (actual time=1488.977..45494.234 rows=15338582 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=280208 read=9857 written=7
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14924586 width=8) (actual time=0.045..10382.166 rows=14838561 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%requests%'::text)
                           Rows Removed by Filter: 161439
                           Buffers: shared hit=244930 read=9857 written=7
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1487.230..1487.230 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=0.016..769.617 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 63475.528 ms
(21 rows)

COMMIT;
COMMIT