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', '17', '33', '34', '15', '14', '22')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '17', '33', '34', '15', '14', '22')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695299.69..695299.70 rows=3 width=20) (actual time=14612.304..14612.304 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=284636 read=42720
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52881.09..52881.10 rows=1 width=4) (actual time=554.359..554.359 rows=1 loops=1)
           Buffers: shared hit=34416 read=1928
           ->  Bitmap Heap Scan on customer  (cost=6640.91..51927.85 rows=381293 width=4) (actual time=138.629..472.695 rows=382032 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,17,33,34,15,14,22}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=34416 read=1928
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6545.59 rows=381293 width=0) (actual time=127.053..127.053 rows=382032 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,17,33,34,15,14,22}'::text[]))
                       Buffers: shared hit=23 read=1043
   ->  HashAggregate  (cost=642418.53..642418.58 rows=3 width=20) (actual time=14612.227..14612.229 rows=7 loops=1)
         Buffers: shared hit=284634 read=42720
         ->  Hash Anti Join  (cost=598403.15..641974.35 rows=59224 width=20) (actual time=14045.481..14587.254 rows=63370 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=284634 read=42720
               ->  Bitmap Heap Scan on customer  (cost=2908.35..41859.86 rows=139943 width=24) (actual time=620.681..844.075 rows=190812 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,17,33,34,15,14,22}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=69598 read=2458
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.37 rows=139943 width=0) (actual time=611.598..611.598 rows=190812 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,17,33,34,15,14,22}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=34433 read=2458
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=13407.956..13407.956 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=215033 read=40262
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.017..5571.951 rows=15015000 loops=1)
                           Buffers: shared hit=215033 read=40262
 Total runtime: 14739.796 ms
(30 rows)

COMMIT;
COMMIT