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
				('11', '33', '30', '13', '12', '23', '27')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '33', '30', '13', '12', '23', '27')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698377.06..698377.07 rows=3 width=20) (actual time=21402.998..21402.999 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=234585 read=94300 dirtied=128 written=2681
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52964.30..52964.31 rows=1 width=4) (actual time=1414.008..1414.008 rows=1 loops=1)
           Buffers: shared hit=12 read=36330
           ->  Bitmap Heap Scan on customer  (cost=6677.49..52007.01 rows=382915 width=4) (actual time=215.458..1300.053 rows=381224 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,33,30,13,12,23,27}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=12 read=36330
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6581.77 rows=382915 width=0) (actual time=202.742..202.742 rows=381224 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,33,30,13,12,23,27}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=645412.68..645412.73 rows=3 width=20) (actual time=21402.923..21402.925 rows=7 loops=1)
         Buffers: shared hit=234583 read=94300 dirtied=128 written=2681
         ->  Hash Anti Join  (cost=601975.72..644971.64 rows=58805 width=20) (actual time=20159.254..21353.739 rows=63616 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=234583 read=94300 dirtied=128 written=2681
               ->  Bitmap Heap Scan on customer  (cost=2940.08..41901.09 rows=140305 width=24) (actual time=1571.447..2348.630 rows=190297 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,33,30,13,12,23,27}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=33976 read=38091 written=138
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.01 rows=140305 width=0) (actual time=1549.976..1549.976 rows=190297 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,33,30,13,12,23,27}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36868
               ->  Hash  (cost=408911.95..408911.95 rows=15209895 width=4) (actual time=18574.031..18574.031 rows=15000000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527344kB
                     Buffers: shared hit=200604 read=56209 dirtied=128 written=2543
                     ->  Seq Scan on orders  (cost=0.00..408911.95 rows=15209895 width=4) (actual time=0.030..10559.218 rows=15000000 loops=1)
                           Buffers: shared hit=200604 read=56209 dirtied=128 written=2543
 Total runtime: 21521.264 ms
(30 rows)

COMMIT;
COMMIT