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', '10', '13', '33', '11', '21', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('25', '10', '13', '33', '11', '21', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695277.89..695277.90 rows=3 width=20) (actual time=26659.003..26659.004 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=286348 read=40984
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52878.27..52878.28 rows=1 width=4) (actual time=3677.558..3677.558 rows=1 loops=1)
           Buffers: shared hit=138 read=36203
           ->  Bitmap Heap Scan on customer  (cost=6640.31..51925.23 rows=381216 width=4) (actual time=283.662..3545.164 rows=381936 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,10,13,33,11,21,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=138 read=36203
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6545.01 rows=381216 width=0) (actual time=272.687..272.687 rows=381936 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{25,10,13,33,11,21,17}'::text[]))
                       Buffers: shared hit=9 read=1054
   ->  HashAggregate  (cost=642399.54..642399.58 rows=3 width=20) (actual time=26658.922..26658.924 rows=7 loops=1)
         Buffers: shared hit=286346 read=40984
         ->  Hash Anti Join  (cost=598401.21..641953.72 rows=59442 width=20) (actual time=24881.252..26602.226 rows=63602 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=286346 read=40984
               ->  Bitmap Heap Scan on customer  (cost=2906.41..41852.98 rows=139755 width=24) (actual time=3842.980..5095.294 rows=190565 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,10,13,33,11,21,17}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35193 read=36839
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.48 rows=139755 width=0) (actual time=3823.715..3823.715 rows=190565 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,10,13,33,11,21,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=149 read=36738
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=21029.077..21029.077 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=251150 read=4145
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.037..13385.990 rows=15015000 loops=1)
                           Buffers: shared hit=251150 read=4145
 Total runtime: 26873.368 ms
(30 rows)

COMMIT;
COMMIT