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=848435.60..848436.10 rows=200 width=8) (actual time=32813.516..32813.519 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=230149 read=59919 written=17
   ->  HashAggregate  (cost=848425.96..848427.96 rows=200 width=8) (actual time=32813.402..32813.410 rows=44 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=230146 read=59919 written=17
         ->  HashAggregate  (cost=810925.96..825925.96 rows=1500000 width=8) (actual time=31953.021..32473.090 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=230146 read=59919 written=17
               ->  Hash Right Join  (cost=69028.00..736304.17 rows=14924358 width=8) (actual time=1308.772..20705.108 rows=15353408 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=230146 read=59919 written=17
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14924358 width=8) (actual time=0.028..9297.445 rows=14853387 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%requests%'::text)
                           Rows Removed by Filter: 161613
                           Buffers: shared hit=230143 read=24644 written=2
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1292.446..1292.446 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=3 read=35275 written=15
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.021..825.570 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275 written=15
 Planning time: 5.488 ms
 Execution time: 32849.139 ms
(24 rows)

COMMIT;
COMMIT