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
				('24', '30', '27', '34', '13', '19', '16')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '30', '27', '34', '13', '19', '16')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695932.61..695932.62 rows=3 width=20) (actual time=30055.567..30055.567 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=255440 read=72177
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52915.58..52915.59 rows=1 width=4) (actual time=3943.982..3943.982 rows=1 loops=1)
           Buffers: shared hit=264 read=36079
           ->  Bitmap Heap Scan on customer  (cost=6648.23..51959.98 rows=382238 width=4) (actual time=283.574..3802.510 rows=381497 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,30,27,34,13,19,16}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=264 read=36079
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.67 rows=382238 width=0) (actual time=268.574..268.574 rows=381497 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,30,27,34,13,19,16}'::text[]))
                       Buffers: shared hit=15 read=1050
   ->  HashAggregate  (cost=643016.96..643017.00 rows=3 width=20) (actual time=30055.486..30055.490 rows=7 loops=1)
         Buffers: shared hit=255438 read=72177
         ->  Hash Anti Join  (cost=598995.23..642569.95 rows=59601 width=20) (actual time=26455.041..29988.396 rows=63519 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=255438 read=72177
               ->  Bitmap Heap Scan on customer  (cost=2910.29..41866.70 rows=140130 width=24) (actual time=4117.050..7208.474 rows=190540 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,30,27,34,13,19,16}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=315 read=71749
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.26 rows=140130 width=0) (actual time=4105.983..4105.983 rows=190540 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,30,27,34,13,19,16}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=275 read=36614
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=22328.142..22328.142 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=255120 read=428
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.030..13870.812 rows=15015000 loops=1)
                           Buffers: shared hit=255120 read=428
 Total runtime: 30143.095 ms
(30 rows)

COMMIT;
COMMIT