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 '%unusual%packages%'
		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=854499.97..854500.47 rows=200 width=8) (actual time=26472.333..26472.336 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=207395 read=84446 written=7
   ->  HashAggregate  (cost=854490.33..854492.33 rows=200 width=8) (actual time=26472.257..26472.265 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=207392 read=84446 written=7
         ->  HashAggregate  (cost=816990.33..831990.33 rows=1500000 width=8) (actual time=25704.254..26142.257 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=207392 read=84446 written=7
               ->  Hash Right Join  (cost=69028.00..741623.84 rows=15073297 width=8) (actual time=815.693..17298.463 rows=15337891 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=207392 read=84446 written=7
                     ->  Seq Scan on orders  (cost=0.00..446496.39 rows=15073297 width=8) (actual time=0.020..7734.404 rows=14837871 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162129
                           Buffers: shared hit=172117 read=84443 written=7
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=809.460..809.460 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35275 read=3
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.010..420.993 rows=1500000 loops=1)
                                 Buffers: shared hit=35275 read=3
 Planning time: 2.445 ms
 Execution time: 26486.445 ms
(24 rows)

COMMIT;
COMMIT