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=918253.44..918253.94 rows=200 width=8) (actual time=32562.357..32562.359 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=280266 read=8537
   ->  HashAggregate  (cost=918243.80..918245.80 rows=200 width=8) (actual time=32562.224..32562.231 rows=46 loops=1)
         Buffers: shared hit=280263 read=8537
         ->  HashAggregate  (cost=880743.80..895743.80 rows=1500000 width=8) (actual time=31818.778..32256.949 rows=1500000 loops=1)
               Buffers: shared hit=280263 read=8537
               ->  Hash Right Join  (cost=69028.00..806642.50 rows=14820260 width=8) (actual time=750.400..23996.597 rows=15354119 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=280263 read=8537
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14820260 width=8) (actual time=0.036..8909.972 rows=14854097 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160903
                           Buffers: shared hit=252467 read=1055
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=748.957..748.957 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=27796 read=7482
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.023..439.680 rows=1500000 loops=1)
                                 Buffers: shared hit=27796 read=7482
 Total runtime: 32580.886 ms
(21 rows)

COMMIT;
COMMIT