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', '31', '13', '15', '24', '20', '12')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('33', '31', '13', '15', '24', '20', '12')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697071.15..697071.16 rows=3 width=20) (actual time=10463.634..10463.636 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=277951 read=50162 dirtied=253 written=537
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52925.04..52925.05 rows=1 width=4) (actual time=595.868..595.868 rows=1 loops=1)
           Buffers: shared hit=25306 read=11037 written=13
           ->  Bitmap Heap Scan on customer customer_1  (cost=6651.12..51968.87 rows=382467 width=4) (actual time=103.028..521.080 rows=382110 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,31,13,15,24,20,12}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=25306 read=11037 written=13
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6555.50 rows=382467 width=0) (actual time=93.862..93.862 rows=382110 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{33,31,13,15,24,20,12}'::text[]))
                       Buffers: shared hit=8 read=1057 written=4
   ->  HashAggregate  (cost=644146.03..644146.07 rows=3 width=20) (actual time=10463.568..10463.570 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=277948 read=50162 dirtied=253 written=537
         ->  Hash Anti Join  (cost=600175.29..643699.87 rows=59488 width=20) (actual time=9719.378..10438.361 rows=63562 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=277948 read=50162 dirtied=253 written=537
               ->  Bitmap Heap Scan on customer  (cost=2910.08..41863.34 rows=140010 width=24) (actual time=656.878..1201.740 rows=190863 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,31,13,15,24,20,12}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35162
                     Buffers: shared hit=25317 read=46736 written=395
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.07 rows=140010 width=0) (actual time=648.321..648.321 rows=190863 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,31,13,15,24,20,12}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25315 read=11576 written=13
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=8971.891..8971.891 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=252628 read=3426 dirtied=253 written=142
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.030..4369.062 rows=15000000 loops=1)
                           Buffers: shared hit=252628 read=3426 dirtied=253 written=142
 Planning time: 2.496 ms
 Execution time: 10478.644 ms
(34 rows)

COMMIT;
COMMIT