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
				('24', '19', '27', '29', '30', '13', '26')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '19', '27', '29', '30', '13', '26')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693447.81..693447.81 rows=3 width=20) (actual time=14016.030..14016.030 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=231273 read=95332 dirtied=229 written=344
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52866.02..52866.03 rows=1 width=4) (actual time=851.941..851.941 rows=1 loops=1)
           Buffers: shared hit=11 read=36330 written=299
           ->  Bitmap Heap Scan on customer customer_1  (cost=6638.58..51913.90 rows=380850 width=4) (actual time=102.746..778.358 rows=381116 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,19,27,29,30,13,26}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=11 read=36330 written=299
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6543.37 rows=380850 width=0) (actual time=93.520..93.520 rows=381116 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,19,27,29,30,13,26}'::text[]))
                       Buffers: shared hit=9 read=1054 written=3
   ->  HashAggregate  (cost=640581.70..640581.75 rows=3 width=20) (actual time=14015.973..14015.975 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=231270 read=95332 dirtied=229 written=344
         ->  Hash Anti Join  (cost=596625.76..640140.78 rows=58790 width=20) (actual time=13190.358..13991.211 rows=63648 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=231270 read=95332 dirtied=229 written=344
               ->  Bitmap Heap Scan on customer  (cost=2906.06..41848.90 rows=139613 width=24) (actual time=917.030..1521.385 rows=190359 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,19,27,29,30,13,26}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35179
                     Buffers: shared hit=23 read=72042 written=341
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.15 rows=139613 width=0) (actual time=907.920..907.920 rows=190359 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,19,27,29,30,13,26}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36865 written=302
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=12094.816..12094.816 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=231244 read=23290 dirtied=229 written=3
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.025..4778.973 rows=15015000 loops=1)
                           Buffers: shared hit=231244 read=23290 dirtied=229 written=3
 Planning time: 3.155 ms
 Execution time: 14041.086 ms
(34 rows)

COMMIT;
COMMIT