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
				('12', '13', '25', '34', '22', '19', '11')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('12', '13', '25', '34', '22', '19', '11')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695225.89..695225.89 rows=3 width=20) (actual time=11326.551..11326.552 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=204709 read=122661 dirtied=254 written=113
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52860.46..52860.47 rows=1 width=4) (actual time=828.073..828.073 rows=1 loops=1)
           Buffers: shared hit=11 read=36330 written=33
           ->  Bitmap Heap Scan on customer customer_1  (cost=6637.39..51908.71 rows=380698 width=4) (actual time=98.054..757.139 rows=381387 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,25,34,22,19,11}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=11 read=36330 written=33
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6542.22 rows=380698 width=0) (actual time=89.049..89.049 rows=381387 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{12,13,25,34,22,19,11}'::text[]))
                       Buffers: shared hit=9 read=1054 written=1
   ->  HashAggregate  (cost=642365.35..642365.39 rows=3 width=20) (actual time=11326.489..11326.492 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=204706 read=122661 dirtied=254 written=113
         ->  Hash Anti Join  (cost=598401.29..641926.36 rows=58531 width=20) (actual time=10931.252..11305.339 rows=63350 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=204706 read=122661 dirtied=254 written=113
               ->  Bitmap Heap Scan on customer  (cost=2906.49..41850.56 rows=139660 width=24) (actual time=892.746..1135.206 rows=190409 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,25,34,22,19,11}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35183
                     Buffers: shared hit=35203 read=36866 written=34
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.57 rows=139660 width=0) (actual time=883.643..883.643 rows=190409 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,25,34,22,19,11}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36866 written=34
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=9827.851..9827.851 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=169500 read=85795 dirtied=254 written=79
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.029..5062.004 rows=15015000 loops=1)
                           Buffers: shared hit=169500 read=85795 dirtied=254 written=79
 Planning time: 3.184 ms
 Execution time: 11345.802 ms
(34 rows)

COMMIT;
COMMIT