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 '%special%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=847729.50..847730.00 rows=200 width=8) (actual time=30774.367..30774.370 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=187802 read=101507 written=263
   ->  HashAggregate  (cost=847719.86..847721.86 rows=200 width=8) (actual time=30774.267..30774.276 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=187799 read=101507 written=263
         ->  HashAggregate  (cost=810219.86..825219.86 rows=1500000 width=8) (actual time=29882.176..30451.821 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=187799 read=101507 written=263
               ->  Hash Right Join  (cost=69028.00..735444.37 rows=14955098 width=8) (actual time=1300.246..19711.690 rows=15353275 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=187799 read=101507 written=263
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14955098 width=8) (actual time=0.029..9067.229 rows=14853258 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161742
                           Buffers: shared hit=187796 read=66232 written=263
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1288.625..1288.625 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=3 read=35275
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.020..833.496 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275
 Planning time: 3.376 ms
 Execution time: 30793.307 ms
(24 rows)

COMMIT;
COMMIT