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
				('11', '16', '32', '15', '20', '30', '19')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '16', '32', '15', '20', '30', '19')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694697.89..694697.90 rows=3 width=20) (actual time=14365.489..14365.490 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=277992 read=49122 dirtied=40 written=11014
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52882.36..52882.37 rows=1 width=4) (actual time=926.041..926.042 rows=1 loops=1)
           Buffers: shared hit=10 read=36335 written=10004
           ->  Bitmap Heap Scan on customer  (cost=6641.18..51929.04 rows=381328 width=4) (actual time=95.366..840.050 rows=382589 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,16,32,15,20,30,19}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=10 read=36335 written=10004
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6545.85 rows=381328 width=0) (actual time=86.324..86.324 rows=382589 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,16,32,15,20,30,19}'::text[]))
                       Buffers: shared hit=8 read=1059 written=176
   ->  HashAggregate  (cost=641815.45..641815.49 rows=3 width=20) (actual time=14365.422..14365.425 rows=7 loops=1)
         Buffers: shared hit=277990 read=49122 dirtied=40 written=11014
         ->  Hash Anti Join  (cost=597808.67..641373.47 rows=58930 width=20) (actual time=13775.857..14331.499 rows=63745 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=277990 read=49122 dirtied=40 written=11014
               ->  Bitmap Heap Scan on customer  (cost=2906.34..41852.65 rows=139745 width=24) (actual time=995.108..1197.904 rows=191201 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,16,32,15,20,30,19}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35195 read=36873 written=10198
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.41 rows=139745 width=0) (actual time=985.930..985.930 rows=191201 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,16,32,15,20,30,19}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36873 written=10198
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=12772.958..12772.958 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=242792 read=12249 dirtied=40 written=816
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.034..4885.229 rows=15015000 loops=1)
                           Buffers: shared hit=242792 read=12249 dirtied=40 written=816
 Total runtime: 14506.585 ms
(30 rows)

COMMIT;
COMMIT