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', '34', '28', '15', '31', '19', '13')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '34', '28', '15', '31', '19', '13')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694112.53..694112.53 rows=3 width=20) (actual time=11830.866..11830.867 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=253309 read=73539 dirtied=207 written=59
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52913.74..52913.75 rows=1 width=4) (actual time=580.505..580.505 rows=1 loops=1)
           Buffers: shared hit=30398 read=5946
           ->  Bitmap Heap Scan on customer customer_1  (cost=6648.73..51958.35 rows=382157 width=4) (actual time=97.576..502.887 rows=382615 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,34,28,15,31,19,13}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=30398 read=5946
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6553.19 rows=382157 width=0) (actual time=88.890..88.890 rows=382615 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,34,28,15,31,19,13}'::text[]))
                       Buffers: shared hit=6 read=1060
   ->  HashAggregate  (cost=641198.70..641198.75 rows=3 width=20) (actual time=11830.796..11830.798 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=253306 read=73539 dirtied=207 written=59
         ->  Hash Anti Join  (cost=597221.21..640751.88 rows=59576 width=20) (actual time=11366.732..11809.012 rows=63454 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=253306 read=73539 dirtied=207 written=59
               ->  Bitmap Heap Scan on customer  (cost=2911.37..41867.78 rows=140130 width=24) (actual time=647.041..934.714 rows=191060 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,34,28,15,31,19,13}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35166
                     Buffers: shared hit=60619 read=11436 written=5
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2876.33 rows=140130 width=0) (actual time=638.046..638.046 rows=191060 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,34,28,15,31,19,13}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=30407 read=6482
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=10569.920..10569.920 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=192684 read=62103 dirtied=207 written=54
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.017..4823.019 rows=15015000 loops=1)
                           Buffers: shared hit=192684 read=62103 dirtied=207 written=54
 Planning time: 2.993 ms
 Execution time: 11854.179 ms
(34 rows)

COMMIT;
COMMIT