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
				('17', '32', '29', '12', '22', '26', '13')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '32', '29', '12', '22', '26', '13')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=691171.47..691171.48 rows=3 width=20) (actual time=10813.480..10813.480 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=323980 read=1596
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52888.75..52888.76 rows=1 width=4) (actual time=469.006..469.006 rows=1 loops=1)
           Buffers: shared hit=35286 read=1057
           ->  Bitmap Heap Scan on customer  (cost=6642.54..51934.99 rows=381503 width=4) (actual time=93.905..393.562 rows=381680 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,32,29,12,22,26,13}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35286 read=1057
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6547.16 rows=381503 width=0) (actual time=85.601..85.601 rows=381680 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,32,29,12,22,26,13}'::text[]))
                       Buffers: shared hit=8 read=1057
   ->  HashAggregate  (cost=638282.64..638282.69 rows=3 width=20) (actual time=10813.406..10813.407 rows=7 loops=1)
         Buffers: shared hit=323978 read=1596
         ->  Hash Anti Join  (cost=594267.99..637836.78 rows=59449 width=20) (actual time=10393.548..10792.909 rows=63463 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=323978 read=1596
               ->  Bitmap Heap Scan on customer  (cost=2908.85..41861.59 rows=139990 width=24) (actual time=522.283..673.313 rows=190758 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,32,29,12,22,26,13}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70453 read=1596
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.86 rows=139990 width=0) (actual time=515.079..515.079 rows=190758 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,32,29,12,22,26,13}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35295 read=1596
               ->  Hash  (cost=403671.84..403671.84 rows=15014984 width=4) (actual time=9856.183..9856.183 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=253522
                     ->  Seq Scan on orders  (cost=0.00..403671.84 rows=15014984 width=4) (actual time=0.019..4414.335 rows=15015000 loops=1)
                           Buffers: shared hit=253522
 Total runtime: 10932.393 ms
(30 rows)

COMMIT;
COMMIT