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', '33', '29', '32', '21', '28', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('12', '33', '29', '32', '21', '28', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694278.24..694278.25 rows=3 width=20) (actual time=12533.508..12533.508 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=222373 read=104482 written=24
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52999.06..52999.07 rows=1 width=4) (actual time=785.630..785.631 rows=1 loops=1)
           Buffers: shared hit=30191 read=6151
           ->  Bitmap Heap Scan on customer customer_1  (cost=6685.75..52039.47 rows=383837 width=4) (actual time=217.057..699.053 rows=382575 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,33,29,32,21,28,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35277
                 Buffers: shared hit=30191 read=6151
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6589.79 rows=383837 width=0) (actual time=193.000..193.000 rows=382575 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{12,33,29,32,21,28,17}'::text[]))
                       Buffers: shared hit=9 read=1056
   ->  HashAggregate  (cost=641279.10..641279.15 rows=3 width=20) (actual time=12533.438..12533.442 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=222370 read=104482 written=24
         ->  Hash Anti Join  (cost=597255.09..640834.72 rows=59251 width=20) (actual time=11792.965..12508.797 rows=63789 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=222370 read=104482 written=24
               ->  Bitmap Heap Scan on customer  (cost=2945.25..41916.84 rows=140708 width=24) (actual time=855.320..1427.793 rows=191050 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,33,29,32,21,28,17}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35173
                     Buffers: shared hit=30204 read=41858
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2910.07 rows=140708 width=0) (actual time=845.703..845.703 rows=191050 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,33,29,32,21,28,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=30201 read=6688
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=10623.167..10623.167 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=192163 read=62624 written=24
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.042..5401.201 rows=15015000 loops=1)
                           Buffers: shared hit=192163 read=62624 written=24
 Planning time: 4.641 ms
 Execution time: 12556.300 ms
(34 rows)

COMMIT;
COMMIT