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=919819.92..919820.42 rows=200 width=8) (actual time=65667.963..65667.965 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=225218 read=63838 written=15
   ->  HashAggregate  (cost=919810.27..919812.27 rows=200 width=8) (actual time=65667.856..65667.871 rows=44 loops=1)
         Buffers: shared hit=225215 read=63838 written=15
         ->  HashAggregate  (cost=882310.27..897310.27 rows=1500000 width=8) (actual time=64478.000..65356.935 rows=1500000 loops=1)
               Buffers: shared hit=225215 read=63838 written=15
               ->  Hash Right Join  (cost=69028.00..807983.74 rows=14865307 width=8) (actual time=1437.094..46683.117 rows=15353353 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=225215 read=63838 written=15
                     ->  Seq Scan on orders  (cost=0.00..441649.60 rows=14865307 width=8) (actual time=0.045..10456.226 rows=14853332 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%requests%'::text)
                           Rows Removed by Filter: 161668
                           Buffers: shared hit=189937 read=63838 written=15
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1435.089..1435.089 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..684.355 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 65713.008 ms
(21 rows)

COMMIT;
COMMIT