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%deposits%'
		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=845346.04..845346.54 rows=200 width=8) (actual time=25024.000..25024.003 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=259714 read=29089
   ->  HashAggregate  (cost=845336.40..845338.40 rows=200 width=8) (actual time=25023.867..25023.876 rows=45 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=259711 read=29089
         ->  HashAggregate  (cost=807836.40..822836.40 rows=1500000 width=8) (actual time=24319.061..24729.147 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=259711 read=29089
               ->  Hash Right Join  (cost=69028.00..733436.63 rows=14879955 width=8) (actual time=934.332..16860.390 rows=15354693 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=259711 read=29089
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14879955 width=8) (actual time=0.031..8008.160 rows=14854672 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%deposits%'::text)
                           Rows Removed by Filter: 160328
                           Buffers: shared hit=246741 read=6781
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=926.941..926.941 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=12970 read=22308
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.019..547.777 rows=1500000 loops=1)
                                 Buffers: shared hit=12970 read=22308
 Planning time: 4.983 ms
 Execution time: 25038.486 ms
(24 rows)

COMMIT;
COMMIT