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
				('29', '14', '13', '25', '23', '30', '21')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('29', '14', '13', '25', '23', '30', '21')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694872.48..694872.48 rows=3 width=20) (actual time=17338.555..17338.557 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=249852 read=77251 dirtied=501 written=159
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52973.95..52973.96 rows=1 width=4) (actual time=1477.464..1477.465 rows=1 loops=1)
           Buffers: shared hit=11 read=36331 written=141
           ->  Bitmap Heap Scan on customer  (cost=6679.56..52016.00 rows=383179 width=4) (actual time=181.477..1349.164 rows=381569 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,14,13,25,23,30,21}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=11 read=36331 written=141
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6583.76 rows=383179 width=0) (actual time=171.201..171.201 rows=381569 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{29,14,13,25,23,30,21}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=641898.44..641898.49 rows=3 width=20) (actual time=17338.481..17338.484 rows=7 loops=1)
         Buffers: shared hit=249850 read=77251 dirtied=501 written=159
         ->  Hash Anti Join  (cost=597845.43..641450.61 rows=59711 width=20) (actual time=16142.147..17283.323 rows=63765 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=249850 read=77251 dirtied=501 written=159
               ->  Bitmap Heap Scan on customer  (cost=2943.10..41911.98 rows=140605 width=24) (actual time=1588.817..2292.402 rows=190581 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,14,13,25,23,30,21}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=1395 read=70662 written=141
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2907.95 rows=140605 width=0) (actual time=1575.073..1575.073 rows=190581 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,14,13,25,23,30,21}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=23 read=36867 written=141
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=14541.486..14541.486 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=248452 read=6589 dirtied=501 written=18
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.049..7197.113 rows=15015000 loops=1)
                           Buffers: shared hit=248452 read=6589 dirtied=501 written=18
 Total runtime: 17537.517 ms
(30 rows)

COMMIT;
COMMIT