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 '%pending%accounts%'
		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=852463.69..852464.19 rows=200 width=8) (actual time=27213.656..27213.658 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=245130 read=45699 written=358
   ->  HashAggregate  (cost=852454.05..852456.05 rows=200 width=8) (actual time=27213.589..27213.594 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=245127 read=45699 written=358
         ->  HashAggregate  (cost=814954.05..829954.05 rows=1500000 width=8) (actual time=26391.666..26881.670 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=245127 read=45699 written=358
               ->  Hash Right Join  (cost=69028.00..739656.33 rows=15059543 width=8) (actual time=1182.411..17081.065 rows=15338266 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=245127 read=45699 written=358
                     ->  Seq Scan on orders  (cost=0.00..444735.19 rows=15059543 width=8) (actual time=0.017..6787.635 rows=14838250 loops=1)
                           Filter: ((o_comment)::text !~~ '%pending%accounts%'::text)
                           Rows Removed by Filter: 161750
                           Buffers: shared hit=245123 read=10425 written=339
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1172.608..1172.608 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=4 read=35274 written=19
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.009..748.825 rows=1500000 loops=1)
                                 Buffers: shared hit=4 read=35274 written=19
 Planning time: 2.615 ms
 Execution time: 27231.099 ms
(24 rows)

COMMIT;
COMMIT