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
				('12', '21', '13', '23', '25', '17', '11')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('12', '21', '13', '23', '25', '17', '11')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694109.85..694109.85 rows=3 width=20) (actual time=11620.596..11620.597 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=244432 read=82428 dirtied=20 written=29
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52899.41..52899.42 rows=1 width=4) (actual time=536.803..536.804 rows=1 loops=1)
           Buffers: shared hit=35287 read=1053
           ->  Bitmap Heap Scan on customer customer_1  (cost=6645.69..51944.99 rows=381764 width=4) (actual time=93.139..456.877 rows=381595 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,21,13,23,25,17,11}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35287 read=1053
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.25 rows=381764 width=0) (actual time=84.474..84.474 rows=381595 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{12,21,13,23,25,17,11}'::text[]))
                       Buffers: shared hit=9 read=1053
   ->  HashAggregate  (cost=641210.36..641210.41 rows=3 width=20) (actual time=11620.542..11620.543 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=244429 read=82428 dirtied=20 written=29
         ->  Hash Anti Join  (cost=597220.78..640769.45 rows=58788 width=20) (actual time=10889.242..11597.460 rows=63328 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=244429 read=82428 dirtied=20 written=29
               ->  Bitmap Heap Scan on customer  (cost=2910.94..41866.38 rows=140093 width=24) (actual time=599.541..1172.881 rows=190443 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,21,13,23,25,17,11}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35181
                     Buffers: shared hit=35658 read=36409 written=8
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.91 rows=140093 width=0) (actual time=590.715..590.715 rows=190443 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,21,13,23,25,17,11}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35296 read=1590
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=10171.746..10171.746 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=208768 read=46019 dirtied=20 written=21
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.030..4723.874 rows=15015000 loops=1)
                           Buffers: shared hit=208768 read=46019 dirtied=20 written=21
 Planning time: 2.452 ms
 Execution time: 11625.370 ms
(34 rows)

COMMIT;
COMMIT