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', '12', '13', '24', '25', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('15', '32', '12', '13', '24', '25', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694697.55..694697.56 rows=3 width=20) (actual time=9836.981..9836.981 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=203921 read=123194 dirtied=128 written=6167
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52902.36..52902.37 rows=1 width=4) (actual time=648.179..648.179 rows=1 loops=1)
           Buffers: shared hit=15 read=36326
           ->  Bitmap Heap Scan on customer customer_1  (cost=6646.29..51947.75 rows=381846 width=4) (actual time=79.182..582.110 rows=381772 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,12,13,24,25,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=15 read=36326
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.83 rows=381846 width=0) (actual time=71.638..71.638 rows=381772 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{15,32,12,13,24,25,14}'::text[]))
                       Buffers: shared hit=13 read=1050
   ->  HashAggregate  (cost=641795.11..641795.16 rows=3 width=20) (actual time=9836.919..9836.921 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=203918 read=123194 dirtied=128 written=6167
         ->  Hash Anti Join  (cost=597812.26..641354.34 rows=58770 width=20) (actual time=9509.496..9817.242 rows=63296 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=203918 read=123194 dirtied=128 written=6167
               ->  Bitmap Heap Scan on customer  (cost=2909.93..41862.72 rows=139992 width=24) (actual time=701.549..875.223 rows=190519 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,12,13,24,25,14}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35181
                     Buffers: shared hit=35207 read=36861
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.93 rows=139992 width=0) (actual time=693.952..693.952 rows=190519 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,32,12,13,24,25,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=26 read=36861
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=8712.164..8712.164 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=168708 read=86333 dirtied=128 written=6167
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.043..4363.474 rows=15000000 loops=1)
                           Buffers: shared hit=168708 read=86333 dirtied=128 written=6167
 Planning time: 2.557 ms
 Execution time: 9859.185 ms
(34 rows)

COMMIT;
COMMIT