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
				('28', '11', '30', '32', '34', '33', '16')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('28', '11', '30', '32', '34', '33', '16')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698419.59..698419.60 rows=3 width=20) (actual time=16198.584..16198.585 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=252901 read=75972 dirtied=253 written=12
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52989.54..52989.55 rows=1 width=4) (actual time=900.438..900.438 rows=1 loops=1)
           Buffers: shared hit=35190 read=1154
           ->  Bitmap Heap Scan on customer  (cost=6682.86..52030.52 rows=383606 width=4) (actual time=227.436..766.062 rows=382140 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,11,30,32,34,33,16}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35190 read=1154
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6586.96 rows=383606 width=0) (actual time=206.025..206.025 rows=382140 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{28,11,30,32,34,33,16}'::text[]))
                       Buffers: shared hit=9 read=1057
   ->  HashAggregate  (cost=645429.98..645430.02 rows=3 width=20) (actual time=16198.505..16198.507 rows=7 loops=1)
         Buffers: shared hit=252899 read=75972 dirtied=253 written=12
         ->  Hash Anti Join  (cost=601978.30..644988.14 rows=58911 width=20) (actual time=15127.557..16150.781 rows=63779 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=252899 read=75972 dirtied=253 written=12
               ->  Bitmap Heap Scan on customer  (cost=2942.67..41910.31 rows=140558 width=24) (actual time=1011.935..1621.845 rows=191062 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,11,30,32,34,33,16}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=51606 read=20449 written=12
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2907.53 rows=140558 width=0) (actual time=998.016..998.016 rows=191062 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,11,30,32,34,33,16}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35200 read=1692
               ->  Hash  (cost=408911.95..408911.95 rows=15209895 width=4) (actual time=14105.962..14105.962 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=201290 read=55523 dirtied=253
                     ->  Seq Scan on orders  (cost=0.00..408911.95 rows=15209895 width=4) (actual time=0.066..6807.131 rows=15015000 loops=1)
                           Buffers: shared hit=201290 read=55523 dirtied=253
 Total runtime: 16294.975 ms
(30 rows)

COMMIT;
COMMIT