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
				('29', '26', '20', '13', '17', '25', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('29', '26', '20', '13', '17', '25', '32')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697010.47..697010.48 rows=3 width=20) (actual time=30339.644..30339.644 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=243042 read=85069 dirtied=17 written=1093
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52856.38..52856.39 rows=1 width=4) (actual time=4212.505..4212.505 rows=1 loops=1)
           Buffers: shared hit=205 read=36137
           ->  Bitmap Heap Scan on customer  (cost=6635.70..51904.84 rows=380615 width=4) (actual time=305.274..4082.662 rows=381918 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,26,20,13,17,25,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=205 read=36137
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6540.55 rows=380615 width=0) (actual time=285.272..285.272 rows=381918 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{29,26,20,13,17,25,32}'::text[]))
                       Buffers: shared hit=7 read=1057
   ->  HashAggregate  (cost=644154.01..644154.06 rows=3 width=20) (actual time=30339.564..30339.567 rows=7 loops=1)
         Buffers: shared hit=243040 read=85069 dirtied=17 written=1093
         ->  Hash Anti Join  (cost=600169.41..643708.90 rows=59348 width=20) (actual time=27456.601..30277.483 rows=63768 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=243040 read=85069 dirtied=17 written=1093
               ->  Bitmap Heap Scan on customer  (cost=2904.19..41844.98 rows=139535 width=24) (actual time=4379.665..6777.590 rows=190940 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,26,20,13,17,25,32}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=17110 read=54942 written=796
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2869.31 rows=139535 width=0) (actual time=4366.523..4366.523 rows=190940 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,26,20,13,17,25,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=214 read=36677
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=23062.539..23062.539 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=225927 read=30127 dirtied=17 written=297
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.042..15042.851 rows=15015000 loops=1)
                           Buffers: shared hit=225927 read=30127 dirtied=17 written=297
 Total runtime: 30412.506 ms
(30 rows)

COMMIT;
COMMIT