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
				('19', '34', '31', '25', '28', '14', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '34', '31', '25', '28', '14', '29')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=696329.75..696329.76 rows=3 width=20) (actual time=20124.822..20124.823 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=286066 read=41556
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52851.59..52851.60 rows=1 width=4) (actual time=2213.766..2213.766 rows=1 loops=1)
           Buffers: shared hit=11 read=36332
           ->  Bitmap Heap Scan on customer  (cost=6634.67..51900.37 rows=380484 width=4) (actual time=261.246..2087.998 rows=381826 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,31,25,28,14,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=11 read=36332
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6539.55 rows=380484 width=0) (actual time=245.005..245.005 rows=381826 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,34,31,25,28,14,29}'::text[]))
                       Buffers: shared hit=8 read=1057
   ->  HashAggregate  (cost=643478.09..643478.13 rows=3 width=20) (actual time=20124.756..20124.758 rows=7 loops=1)
         Buffers: shared hit=286064 read=41556
         ->  Hash Anti Join  (cost=598988.48..643035.52 rows=59009 width=20) (actual time=19377.725..20089.455 rows=63648 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=286064 read=41556
               ->  Bitmap Heap Scan on customer  (cost=2903.55..41842.84 rows=139478 width=24) (actual time=2331.113..2672.831 rows=190785 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,31,25,28,14,29}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35196 read=36873
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.68 rows=139478 width=0) (actual time=2313.988..2313.988 rows=190785 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,31,25,28,14,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36870
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=17036.143..17036.143 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=250865 read=4683
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.038..7208.905 rows=15015000 loops=1)
                           Buffers: shared hit=250865 read=4683
 Total runtime: 20240.178 ms
(30 rows)

COMMIT;
COMMIT