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
				('34', '30', '24', '31', '14', '12', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('34', '30', '24', '31', '14', '12', '29')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695284.69..695284.69 rows=3 width=20) (actual time=17287.223..17287.224 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=319439 read=8183 dirtied=22 written=6
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52885.37..52885.38 rows=1 width=4) (actual time=693.495..693.495 rows=1 loops=1)
           Buffers: shared hit=35286 read=1056
           ->  Bitmap Heap Scan on customer  (cost=6641.83..51931.84 rows=381410 width=4) (actual time=145.126..577.092 rows=381090 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,30,24,31,14,12,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35286 read=1056
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6546.48 rows=381410 width=0) (actual time=132.903..132.903 rows=381090 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{34,30,24,31,14,12,29}'::text[]))
                       Buffers: shared hit=8 read=1056
   ->  HashAggregate  (cost=642399.24..642399.28 rows=3 width=20) (actual time=17287.151..17287.155 rows=7 loops=1)
         Buffers: shared hit=319437 read=8183 dirtied=22 written=6
         ->  Hash Anti Join  (cost=598992.86..641954.30 rows=59325 width=20) (actual time=16588.033..17259.487 rows=63741 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=319437 read=8183 dirtied=22 written=6
               ->  Bitmap Heap Scan on customer  (cost=2907.92..41858.35 rows=139902 width=24) (actual time=770.151..1064.707 rows=190530 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,30,24,31,14,12,29}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=65218 read=6851
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2872.95 rows=139902 width=0) (actual time=760.016..760.016 rows=190530 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,30,24,31,14,12,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35296 read=1594
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=15807.102..15807.102 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=254216 read=1332 dirtied=22 written=6
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.018..5791.991 rows=15015000 loops=1)
                           Buffers: shared hit=254216 read=1332 dirtied=22 written=6
 Total runtime: 17417.842 ms
(30 rows)

COMMIT;
COMMIT