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
				('22', '21', '15', '19', '12', '18', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('22', '21', '15', '19', '12', '18', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693059.25..693059.26 rows=3 width=20) (actual time=13772.692..13772.693 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=270682 read=55653 dirtied=1 written=1383
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52990.60..52990.61 rows=1 width=4) (actual time=524.748..524.748 rows=1 loops=1)
           Buffers: shared hit=28161 read=8184 written=433
           ->  Bitmap Heap Scan on customer customer_1  (cost=6683.96..52031.59 rows=383605 width=4) (actual time=90.009..452.287 rows=382474 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,21,15,19,12,18,30}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=28161 read=8184 written=433
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6588.06 rows=383605 width=0) (actual time=81.613..81.613 rows=382474 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{22,21,15,19,12,18,30}'::text[]))
                       Buffers: shared hit=9 read=1058 written=55
   ->  HashAggregate  (cost=640068.57..640068.61 rows=3 width=20) (actual time=13772.619..13772.622 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=270679 read=55653 dirtied=1 written=1383
         ->  Hash Anti Join  (cost=596071.94..639621.08 rows=59665 width=20) (actual time=13252.676..13749.985 rows=63701 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=270679 read=55653 dirtied=1 written=1383
               ->  Bitmap Heap Scan on customer  (cost=2942.38..41906.59 rows=140427 width=24) (actual time=584.252..898.271 rows=190955 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,21,15,19,12,18,30}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35156
                     Buffers: shared hit=57357 read=14691 written=461
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2907.27 rows=140427 width=0) (actual time=575.833..575.833 rows=190955 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,21,15,19,12,18,30}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=28170 read=8722 written=461
               ->  Hash  (cost=404880.36..404880.36 rows=15059936 width=4) (actual time=12545.039..12545.039 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=213319 read=40962 dirtied=1 written=922
                     ->  Seq Scan on orders  (cost=0.00..404880.36 rows=15059936 width=4) (actual time=0.019..5426.237 rows=15000000 loops=1)
                           Buffers: shared hit=213319 read=40962 dirtied=1 written=922
 Planning time: 2.779 ms
 Execution time: 13801.508 ms
(34 rows)

COMMIT;
COMMIT