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=851051.89..851052.39 rows=200 width=8) (actual time=31298.684..31298.687 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=247800 read=43788 written=40
   ->  HashAggregate  (cost=851042.25..851044.25 rows=200 width=8) (actual time=31298.594..31298.604 rows=45 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=247797 read=43788 written=40
         ->  HashAggregate  (cost=813542.25..828542.25 rows=1500000 width=8) (actual time=30359.812..30977.215 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=247797 read=43788 written=40
               ->  Hash Right Join  (cost=69028.00..738927.71 rows=14922908 width=8) (actual time=911.743..18934.126 rows=15354111 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=247797 read=43788 written=40
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=14922908 width=8) (actual time=0.027..8601.259 rows=14854091 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160909
                           Buffers: shared hit=212519 read=43788 written=40
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=900.947..900.947 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..483.364 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.718 ms
 Execution time: 31320.760 ms
(24 rows)

COMMIT;
COMMIT