BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	cntrycode,
	count(*) as numcust,
	sum(c_acctbal) as totacctbal
from
	(
		select
			substr(c_phone, 1, 2) as cntrycode,
			c_acctbal
		from
			customer
		where
			substr(c_phone, 1, 2) in
				('25', '12', '15', '29', '28', '32', '16')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('25', '12', '15', '29', '28', '32', '16')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694744.31..694744.32 rows=3 width=20) (actual time=16866.774..16866.774 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=138168 read=189200 dirtied=254 written=500
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52914.92..52914.93 rows=1 width=4) (actual time=967.694..967.694 rows=1 loops=1)
           Buffers: shared hit=9183 read=27161 written=41
           ->  Bitmap Heap Scan on customer  (cost=6648.12..51959.37 rows=382219 width=4) (actual time=147.743..863.785 rows=382485 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,12,15,29,28,32,16}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=9183 read=27161 written=41
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.57 rows=382219 width=0) (actual time=135.375..135.375 rows=382485 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{25,12,15,29,28,32,16}'::text[]))
                       Buffers: shared hit=9 read=1057
   ->  HashAggregate  (cost=641829.31..641829.36 rows=3 width=20) (actual time=16866.657..16866.659 rows=7 loops=1)
         Buffers: shared hit=138166 read=189200 dirtied=254 written=500
         ->  Hash Anti Join  (cost=598405.73..641383.44 rows=59450 width=20) (actual time=15867.898..16834.396 rows=63531 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=138166 read=189200 dirtied=254 written=500
               ->  Bitmap Heap Scan on customer  (cost=2910.94..41869.13 rows=140198 width=24) (actual time=1078.253..1639.663 rows=191139 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,12,15,29,28,32,16}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=9195 read=62873 written=41
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.89 rows=140198 width=0) (actual time=1063.980..1063.980 rows=191139 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,12,15,29,28,32,16}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=9193 read=27700 written=41
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=14771.126..14771.126 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=128968 read=126327 dirtied=254 written=459
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.031..6244.761 rows=15015000 loops=1)
                           Buffers: shared hit=128968 read=126327 dirtied=254 written=459
 Total runtime: 17020.049 ms
(30 rows)

COMMIT;
COMMIT