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
				('19', '22', '34', '28', '26', '23', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '22', '34', '28', '26', '23', '29')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697006.52..697006.53 rows=3 width=20) (actual time=15238.214..15238.215 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=303995 read=24136 written=21
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52873.66..52873.67 rows=1 width=4) (actual time=734.537..734.537 rows=1 loops=1)
           Buffers: shared hit=35743 read=600
           ->  Bitmap Heap Scan on customer customer_1  (cost=6640.21..51921.01 rows=381059 width=4) (actual time=142.139..605.341 rows=381615 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,22,34,28,26,23,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35743 read=600
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6544.95 rows=381059 width=0) (actual time=129.333..129.333 rows=381615 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,22,34,28,26,23,29}'::text[]))
                       Buffers: shared hit=465 read=600
   ->  HashAggregate  (cost=644132.79..644132.83 rows=3 width=20) (actual time=15238.141..15238.144 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=303992 read=24136 written=21
         ->  Hash Anti Join  (cost=600172.06..643691.61 rows=58823 width=20) (actual time=14725.265..15214.070 rows=63383 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=303992 read=24136 written=21
               ->  Bitmap Heap Scan on customer  (cost=2906.85..41851.71 rows=139690 width=24) (actual time=810.023..1136.652 rows=190848 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,22,34,28,26,23,29}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35182
                     Buffers: shared hit=69698 read=2373 written=6
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.92 rows=139690 width=0) (actual time=800.813..800.813 rows=190848 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,22,34,28,26,23,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35983 read=906
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=11626.421..11626.421 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=234291 read=21763 written=15
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.226..5125.549 rows=15015000 loops=1)
                           Buffers: shared hit=234291 read=21763 written=15
 Planning time: 4.116 ms
 Execution time: 15263.477 ms
(34 rows)

COMMIT;
COMMIT