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', '33', '25', '27', '10', '14', '13')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('32', '33', '25', '27', '10', '14', '13')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694681.22..694681.23 rows=3 width=20) (actual time=10099.684..10099.685 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=265932 read=61156 written=31
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52899.95..52899.96 rows=1 width=4) (actual time=474.445..474.446 rows=1 loops=1)
           Buffers: shared hit=34995 read=1345 written=1
           ->  Bitmap Heap Scan on customer customer_1  (cost=6645.80..51945.50 rows=381779 width=4) (actual time=95.063..396.853 rows=381639 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,33,25,27,10,14,13}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=34995 read=1345 written=1
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.35 rows=381779 width=0) (actual time=86.168..86.168 rows=381639 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{32,33,25,27,10,14,13}'::text[]))
                       Buffers: shared hit=166 read=896 written=1
   ->  HashAggregate  (cost=641781.20..641781.24 rows=3 width=20) (actual time=10099.617..10099.618 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=265929 read=61156 written=31
         ->  Hash Anti Join  (cost=597812.26..641334.82 rows=59517 width=20) (actual time=9776.022..10079.173 rows=63566 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=265929 read=61156 written=31
               ->  Bitmap Heap Scan on customer  (cost=2909.93..41862.72 rows=139992 width=24) (actual time=537.476..723.952 rows=190418 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,33,25,27,10,14,13}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35156
                     Buffers: shared hit=70240 read=1801 written=1
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.93 rows=139992 width=0) (actual time=528.786..528.786 rows=190418 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,33,25,27,10,14,13}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35084 read=1801 written=1
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=9135.851..9135.851 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=195686 read=59355 written=30
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.034..4422.259 rows=15015000 loops=1)
                           Buffers: shared hit=195686 read=59355 written=30
 Planning time: 2.472 ms
 Execution time: 10126.817 ms
(34 rows)

COMMIT;
COMMIT