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
				('13', '14', '12', '11', '27', '32', '22')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('13', '14', '12', '11', '27', '32', '22')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694648.59..694648.60 rows=3 width=20) (actual time=10616.666..10616.667 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=215855 read=111230 dirtied=254 written=86
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52881.04..52881.05 rows=1 width=4) (actual time=478.673..478.673 rows=1 loops=1)
           Buffers: shared hit=33564 read=2776 written=5
           ->  Bitmap Heap Scan on customer customer_1  (cost=6641.78..51927.89 rows=381261 width=4) (actual time=93.598..405.267 rows=381049 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,14,12,11,27,32,22}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=33564 read=2776 written=5
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6546.47 rows=381261 width=0) (actual time=85.126..85.126 rows=381049 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{13,14,12,11,27,32,22}'::text[]))
                       Buffers: shared hit=10 read=1052
   ->  HashAggregate  (cost=641767.47..641767.51 rows=3 width=20) (actual time=10616.603..10616.606 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=215852 read=111230 dirtied=254 written=86
         ->  Hash Anti Join  (cost=597810.32..641321.70 rows=59436 width=20) (actual time=10225.158..10595.014 rows=63227 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=215852 read=111230 dirtied=254 written=86
               ->  Bitmap Heap Scan on customer  (cost=2907.99..41855.80 rows=139802 width=24) (actual time=539.689..788.443 rows=190186 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,14,12,11,27,32,22}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35153
                     Buffers: shared hit=60032 read=12006 written=5
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.04 rows=139802 width=0) (actual time=531.090..531.090 rows=190186 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,14,12,11,27,32,22}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=33574 read=3311 written=5
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=9146.499..9146.499 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=155817 read=99224 dirtied=254 written=81
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.021..4455.867 rows=15015000 loops=1)
                           Buffers: shared hit=155817 read=99224 dirtied=254 written=81
 Planning time: 2.519 ms
 Execution time: 10640.085 ms
(34 rows)

COMMIT;
COMMIT