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
				('12', '25', '15', '29', '14', '13', '28')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('12', '25', '15', '29', '14', '13', '28')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=691123.36..691123.37 rows=3 width=20) (actual time=9123.010..9123.011 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=324003 read=1589
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52859.70..52859.71 rows=1 width=4) (actual time=454.839..454.839 rows=1 loops=1)
           Buffers: shared hit=35291 read=1052
           ->  Bitmap Heap Scan on customer  (cost=6636.40..51907.94 rows=380706 width=4) (actual time=83.523..380.188 rows=381982 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,25,15,29,14,13,28}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35291 read=1052
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6541.23 rows=380706 width=0) (actual time=76.347..76.347 rows=381982 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{12,25,15,29,14,13,28}'::text[]))
                       Buffers: shared hit=13 read=1052
   ->  HashAggregate  (cost=638263.58..638263.62 rows=3 width=20) (actual time=9122.929..9122.930 rows=7 loops=1)
         Buffers: shared hit=324001 read=1589
         ->  Hash Anti Join  (cost=594264.05..637822.58 rows=58799 width=20) (actual time=8698.978..9103.169 rows=63506 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=324001 read=1589
               ->  Bitmap Heap Scan on customer  (cost=2904.91..41847.62 rows=139608 width=24) (actual time=507.702..654.279 rows=190691 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,25,15,29,14,13,28}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70476 read=1589
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.01 rows=139608 width=0) (actual time=500.479..500.479 rows=190691 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,25,15,29,14,13,28}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35301 read=1589
               ->  Hash  (cost=403671.84..403671.84 rows=15014984 width=4) (actual time=8184.737..8184.737 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=0.025..4313.849 rows=15015000 loops=1)
                           Buffers: shared hit=253522
 Total runtime: 9153.511 ms
(30 rows)

COMMIT;
COMMIT