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
				('33', '23', '13', '14', '21', '31', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('33', '23', '13', '14', '21', '31', '29')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694256.27..694256.27 rows=3 width=20) (actual time=28524.190..28524.191 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=285240 read=41583 dirtied=23 written=33
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52966.63..52966.64 rows=1 width=4) (actual time=2102.829..2102.829 rows=1 loops=1)
           Buffers: shared hit=32221 read=4123
           ->  Bitmap Heap Scan on customer  (cost=6677.98..52009.18 rows=382979 width=4) (actual time=331.654..1970.473 rows=382067 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,23,13,14,21,31,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=32221 read=4123
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6582.24 rows=382979 width=0) (actual time=312.820..312.820 rows=382067 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{33,23,13,14,21,31,29}'::text[]))
                       Buffers: shared hit=7 read=1059
   ->  HashAggregate  (cost=641289.56..641289.60 rows=3 width=20) (actual time=28524.102..28524.105 rows=7 loops=1)
         Buffers: shared hit=285238 read=41583 dirtied=23 written=33
         ->  Hash Anti Join  (cost=597250.86..640841.68 rows=59717 width=20) (actual time=24629.983..28457.309 rows=63610 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=285238 read=41583 dirtied=23 written=33
               ->  Bitmap Heap Scan on customer  (cost=2941.02..41904.57 rows=140402 width=24) (actual time=2329.080..5625.135 rows=190745 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,23,13,14,21,31,29}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=32234 read=39797 written=33
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.92 rows=140402 width=0) (actual time=2310.851..2310.851 rows=190745 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,23,13,14,21,31,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=32231 read=4661
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=22289.762..22289.762 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=253001 read=1786 dirtied=23
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.022..11712.998 rows=15015000 loops=1)
                           Buffers: shared hit=253001 read=1786 dirtied=23
 Total runtime: 28689.946 ms
(30 rows)

COMMIT;
COMMIT