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
				('15', '32', '33', '23', '30', '13', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('15', '32', '33', '23', '30', '13', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695526.83..695526.84 rows=3 width=20) (actual time=13296.489..13296.490 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=205033 read=122321 dirtied=39 written=2713
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=53049.91..53049.92 rows=1 width=4) (actual time=723.955..723.955 rows=1 loops=1)
           Buffers: shared hit=9594 read=26749 written=1
           ->  Bitmap Heap Scan on customer customer_1  (cost=6696.54..52086.83 rows=385230 width=4) (actual time=115.175..651.731 rows=382610 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,33,23,30,13,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35277
                 Buffers: shared hit=9594 read=26749 written=1
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6600.24 rows=385230 width=0) (actual time=104.047..104.047 rows=382610 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{15,32,33,23,30,13,17}'::text[]))
                       Buffers: shared hit=7 read=1059 written=1
   ->  HashAggregate  (cost=642476.84..642476.89 rows=3 width=20) (actual time=13296.427..13296.432 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=205030 read=122321 dirtied=39 written=2713
         ->  Hash Anti Join  (cost=598443.28..642027.46 rows=59918 width=20) (actual time=12850.359..13275.471 rows=63754 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=205030 read=122321 dirtied=39 written=2713
               ->  Bitmap Heap Scan on customer  (cost=2948.48..41928.31 rows=141022 width=24) (actual time=789.072..1016.241 rows=191032 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,33,23,30,13,17}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35163
                     Buffers: shared hit=44458 read=27595 written=2
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2913.22 rows=141022 width=0) (actual time=779.757..779.757 rows=191032 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,33,23,30,13,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=9604 read=27286 written=1
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=11871.654..11871.654 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=160569 read=94726 dirtied=39 written=2711
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.031..4980.899 rows=15000000 loops=1)
                           Buffers: shared hit=160569 read=94726 dirtied=39 written=2711
 Planning time: 2.860 ms
 Execution time: 13313.665 ms
(34 rows)

COMMIT;
COMMIT