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
				('34', '17', '19', '13', '23', '26', '25')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('34', '17', '19', '13', '23', '26', '25')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697617.89..697617.90 rows=3 width=20) (actual time=11556.650..11556.651 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=288602 read=39767 dirtied=31 written=996
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52890.49..52890.50 rows=1 width=4) (actual time=500.412..500.413 rows=1 loops=1)
           Buffers: shared hit=32815 read=3527 written=461
           ->  Bitmap Heap Scan on customer customer_1  (cost=6643.79..51936.69 rows=381520 width=4) (actual time=89.663..428.494 rows=381839 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,17,19,13,23,26,25}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=32815 read=3527 written=461
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6548.41 rows=381520 width=0) (actual time=81.788..81.788 rows=381839 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{34,17,19,13,23,26,25}'::text[]))
                       Buffers: shared hit=7 read=1057 written=139
   ->  HashAggregate  (cost=644727.32..644727.36 rows=3 width=20) (actual time=11556.582..11556.584 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=288599 read=39767 dirtied=31 written=996
         ->  Hash Anti Join  (cost=600764.29..644281.24 rows=59477 width=20) (actual time=11135.545..11535.294 rows=63373 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=288599 read=39767 dirtied=31 written=996
               ->  Bitmap Heap Scan on customer  (cost=2908.93..41859.22 rows=139897 width=24) (actual time=559.094..794.990 rows=190774 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,17,19,13,23,26,25}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35168
                     Buffers: shared hit=67989 read=4067 written=531
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.95 rows=139897 width=0) (actual time=550.864..550.864 rows=190774 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,17,19,13,23,26,25}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=32824 read=4064 written=531
               ->  Hash  (cost=408106.27..408106.27 rows=15179927 width=4) (actual time=9957.798..9957.798 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=220607 read=35700 dirtied=31 written=465
                     ->  Seq Scan on orders  (cost=0.00..408106.27 rows=15179927 width=4) (actual time=0.020..4403.267 rows=15015000 loops=1)
                           Buffers: shared hit=220607 read=35700 dirtied=31 written=465
 Planning time: 2.468 ms
 Execution time: 11572.781 ms
(34 rows)

COMMIT;
COMMIT