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%requests%'
		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=927123.51..927124.01 rows=200 width=8) (actual time=59952.052..59952.055 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=279354 read=11981
   ->  HashAggregate  (cost=927113.86..927115.86 rows=200 width=8) (actual time=59951.954..59951.964 rows=46 loops=1)
         Buffers: shared hit=279351 read=11981
         ->  HashAggregate  (cost=889613.86..904613.86 rows=1500000 width=8) (actual time=58995.435..59641.807 rows=1500000 loops=1)
               Buffers: shared hit=279351 read=11981
               ->  Hash Right Join  (cost=69028.00..814619.85 rows=14998803 width=8) (actual time=1119.711..43314.755 rows=15338649 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=279351 read=11981
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=14998803 width=8) (actual time=0.039..10098.859 rows=14838628 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%requests%'::text)
                           Rows Removed by Filter: 161372
                           Buffers: shared hit=251555 read=4499
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1117.992..1117.992 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=27796 read=7482
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..582.072 rows=1500000 loops=1)
                                 Buffers: shared hit=27796 read=7482
 Total runtime: 59980.737 ms
(21 rows)

COMMIT;
COMMIT