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
				('21', '19', '24', '32', '10', '22', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('21', '19', '24', '32', '10', '22', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=699069.55..699069.56 rows=3 width=20) (actual time=22387.245..22387.246 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=309973 read=18901 dirtied=52 written=171
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=53009.44..53009.45 rows=1 width=4) (actual time=960.923..960.923 rows=1 loops=1)
           Buffers: shared hit=27922 read=8420
           ->  Bitmap Heap Scan on customer  (cost=6687.10..52049.06 rows=384151 width=4) (actual time=158.541..815.267 rows=381637 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{21,19,24,32,10,22,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=27922 read=8420
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6591.06 rows=384151 width=0) (actual time=145.819..145.819 rows=381637 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{21,19,24,32,10,22,14}'::text[]))
                       Buffers: shared hit=7 read=1057
   ->  HashAggregate  (cost=646060.03..646060.07 rows=3 width=20) (actual time=22387.159..22387.163 rows=7 loops=1)
         Buffers: shared hit=309971 read=18901 dirtied=52 written=171
         ->  Hash Anti Join  (cost=601981.53..645615.05 rows=59331 width=20) (actual time=21347.140..22335.148 rows=63295 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=309971 read=18901 dirtied=52 written=171
               ->  Bitmap Heap Scan on customer  (cost=2945.89..41921.78 rows=140872 width=24) (actual time=1072.792..1592.224 rows=190510 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{21,19,24,32,10,22,14}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=63099 read=8957
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2910.68 rows=140872 width=0) (actual time=1061.796..1061.796 rows=190510 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{21,19,24,32,10,22,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=27931 read=8957
               ->  Hash  (cost=408911.95..408911.95 rows=15209895 width=4) (actual time=20261.935..20261.935 rows=15000000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527344kB
                     Buffers: shared hit=246869 read=9944 dirtied=52 written=171
                     ->  Seq Scan on orders  (cost=0.00..408911.95 rows=15209895 width=4) (actual time=0.044..8495.125 rows=15000000 loops=1)
                           Buffers: shared hit=246869 read=9944 dirtied=52 written=171
 Total runtime: 22577.798 ms
(30 rows)

COMMIT;
COMMIT