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
				('32', '29', '20', '31', '33', '15', '13')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('32', '29', '20', '31', '33', '15', '13')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698282.23..698282.24 rows=3 width=20) (actual time=9963.283..9963.284 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=215333 read=113287 dirtied=285 written=318
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52927.91..52927.92 rows=1 width=4) (actual time=714.658..714.659 rows=1 loops=1)
           Buffers: shared hit=11 read=36333 written=228
           ->  Bitmap Heap Scan on customer customer_1  (cost=6651.71..51971.55 rows=382546 width=4) (actual time=97.453..638.905 rows=382725 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,29,20,31,33,15,13}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=11 read=36333 written=228
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6556.08 rows=382546 width=0) (actual time=88.642..88.642 rows=382725 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{32,29,20,31,33,15,13}'::text[]))
                       Buffers: shared hit=9 read=1057 written=2
   ->  HashAggregate  (cost=645354.24..645354.29 rows=3 width=20) (actual time=9963.236..9963.237 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=215330 read=113287 dirtied=285 written=318
         ->  Hash Anti Join  (cost=601358.08..644911.41 rows=59044 width=20) (actual time=9339.732..9934.934 rows=63885 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=215330 read=113287 dirtied=285 written=318
               ->  Bitmap Heap Scan on customer  (cost=2912.59..41872.28 rows=140255 width=24) (actual time=780.136..1244.439 rows=191192 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,29,20,31,33,15,13}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35161
                     Buffers: shared hit=23 read=72031 written=289
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2877.52 rows=140255 width=0) (actual time=771.555..771.555 rows=191192 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,29,20,31,33,15,13}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36872 written=231
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=8487.086..8487.086 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=215304 read=41256 dirtied=285 written=29
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.015..3829.968 rows=15000000 loops=1)
                           Buffers: shared hit=215304 read=41256 dirtied=285 written=29
 Planning time: 2.593 ms
 Execution time: 9967.086 ms
(34 rows)

COMMIT;
COMMIT