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
				('19', '29', '26', '25', '34', '11', '33')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '29', '26', '25', '34', '11', '33')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698141.64..698141.65 rows=3 width=20) (actual time=11784.120..11784.120 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=155675 read=172944 written=206
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52861.40..52861.41 rows=1 width=4) (actual time=782.671..782.671 rows=1 loops=1)
           Buffers: shared hit=11 read=36331 written=15
           ->  Bitmap Heap Scan on customer customer_1  (cost=6637.61..51909.59 rows=380723 width=4) (actual time=96.838..712.533 rows=381853 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,29,26,25,34,11,33}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=11 read=36331 written=15
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6542.43 rows=380723 width=0) (actual time=88.125..88.125 rows=381853 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,29,26,25,34,11,33}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=645280.17..645280.21 rows=3 width=20) (actual time=11784.059..11784.060 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=155672 read=172944 written=206
         ->  Hash Anti Join  (cost=601349.04..644836.04 rows=59217 width=20) (actual time=11041.438..11757.584 rows=63704 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=155672 read=172944 written=206
               ->  Bitmap Heap Scan on customer  (cost=2903.55..41840.06 rows=139372 width=24) (actual time=843.110..1402.225 rows=190766 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,29,26,25,34,11,33}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35164
                     Buffers: shared hit=22 read=72031 written=90
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.70 rows=139372 width=0) (actual time=834.584..834.584 rows=190766 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,29,26,25,34,11,33}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36869 written=15
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=10057.431..10057.431 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=155647 read=100913 written=116
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.020..5069.368 rows=15015000 loops=1)
                           Buffers: shared hit=155647 read=100913 written=116
 Planning time: 3.103 ms
 Execution time: 11813.489 ms
(34 rows)

COMMIT;
COMMIT