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=847538.14..847538.64 rows=200 width=8) (actual time=30946.803..30946.807 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=208909 read=81159 written=677
   ->  HashAggregate  (cost=847528.50..847530.50 rows=200 width=8) (actual time=30946.707..30946.715 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=208906 read=81159 written=677
         ->  HashAggregate  (cost=810028.50..825028.50 rows=1500000 width=8) (actual time=29936.985..30620.576 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=208906 read=81159 written=677
               ->  Hash Right Join  (cost=69028.00..735631.08 rows=14879485 width=8) (actual time=1116.193..18789.867 rows=15354699 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=208906 read=81159 written=677
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14879485 width=8) (actual time=0.038..8539.007 rows=14854680 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%deposits%'::text)
                           Rows Removed by Filter: 160320
                           Buffers: shared hit=208904 read=45883 written=677
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1108.707..1108.707 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.008..699.479 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276
 Planning time: 3.091 ms
 Execution time: 30968.547 ms
(24 rows)

COMMIT;
COMMIT