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', '24', '13', '20', '10', '27', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('29', '24', '13', '20', '10', '27', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693425.47..693425.48 rows=3 width=20) (actual time=10780.552..10780.553 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=163852 read=162730 written=60
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52844.85..52844.86 rows=1 width=4) (actual time=726.141..726.141 rows=1 loops=1)
           Buffers: shared hit=9 read=36330
           ->  Bitmap Heap Scan on customer customer_1  (cost=6634.08..51894.17 rows=380270 width=4) (actual time=86.232..656.376 rows=380956 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,24,13,20,10,27,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=9 read=36330
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6539.01 rows=380270 width=0) (actual time=77.913..77.913 rows=380956 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{29,24,13,20,10,27,14}'::text[]))
                       Buffers: shared hit=7 read=1054
   ->  HashAggregate  (cost=640580.55..640580.59 rows=3 width=20) (actual time=10780.499..10780.500 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=163849 read=162730 written=60
         ->  Hash Anti Join  (cost=596625.04..640141.36 rows=58558 width=20) (actual time=10116.051..10756.742 rows=63559 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=163849 read=162730 written=60
               ->  Bitmap Heap Scan on customer  (cost=2905.34..41846.40 rows=139545 width=24) (actual time=786.022..1289.504 rows=190210 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,24,13,20,10,27,14}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35158
                     Buffers: shared hit=21 read=72021
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.45 rows=139545 width=0) (actual time=777.687..777.687 rows=190210 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,24,13,20,10,27,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=19 read=36865
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=9231.547..9231.547 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=163825 read=90709 written=60
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.020..4636.970 rows=15015000 loops=1)
                           Buffers: shared hit=163825 read=90709 written=60
 Planning time: 2.898 ms
 Execution time: 10800.787 ms
(34 rows)

COMMIT;
COMMIT