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%packages%'
		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=928790.43..928790.93 rows=200 width=8) (actual time=89002.664..89002.667 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=250162 read=41932 written=247
   ->  HashAggregate  (cost=928780.79..928782.79 rows=200 width=8) (actual time=89002.543..89002.552 rows=46 loops=1)
         Buffers: shared hit=250159 read=41932 written=247
         ->  HashAggregate  (cost=891280.79..906280.79 rows=1500000 width=8) (actual time=87727.923..88616.003 rows=1500000 loops=1)
               Buffers: shared hit=250159 read=41932 written=247
               ->  Hash Right Join  (cost=69028.00..816217.57 rows=15012644 width=8) (actual time=4015.340..63902.767 rows=15354132 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=250159 read=41932 written=247
                     ->  Seq Scan on orders  (cost=0.00..446936.69 rows=15012644 width=8) (actual time=0.045..19433.564 rows=14854112 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160888
                           Buffers: shared hit=247764 read=9049 written=227
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=4013.023..4013.023 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2395 read=32883 written=20
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.011..3150.174 rows=1500000 loops=1)
                                 Buffers: shared hit=2395 read=32883 written=20
 Total runtime: 89046.066 ms
(21 rows)

COMMIT;
COMMIT