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', '29', '22', '34', '25', '13', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '29', '22', '34', '25', '13', '32')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=696431.00..696431.01 rows=3 width=20) (actual time=16397.274..16397.275 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=242289 read=85571 written=213
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52882.12..52882.13 rows=1 width=4) (actual time=633.843..633.843 rows=1 loops=1)
           Buffers: shared hit=35272 read=1069 written=1
           ->  Bitmap Heap Scan on customer customer_1  (cost=6642.00..51928.89 rows=381291 width=4) (actual time=143.578..538.268 rows=381773 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,29,22,34,25,13,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35272 read=1069 written=1
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6546.68 rows=381291 width=0) (actual time=131.557..131.557 rows=381773 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,29,22,34,25,13,32}'::text[]))
                       Buffers: shared hit=6 read=1057 written=1
   ->  HashAggregate  (cost=643548.80..643548.85 rows=3 width=20) (actual time=16397.196..16397.199 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=242286 read=85571 written=213
         ->  Hash Anti Join  (cost=599582.79..643107.37 rows=58858 width=20) (actual time=15710.415..16356.143 rows=63631 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=242286 read=85571 written=213
               ->  Bitmap Heap Scan on customer  (cost=2907.71..41854.80 rows=139775 width=24) (actual time=695.861..1102.402 rows=190734 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,29,22,34,25,13,32}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35165
                     Buffers: shared hit=62512 read=9541 written=24
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2872.76 rows=139775 width=0) (actual time=687.084..687.084 rows=190734 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,29,22,34,25,13,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35281 read=1607 written=1
               ->  Hash  (cost=407300.59..407300.59 rows=15149959 width=4) (actual time=14879.768..14879.768 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=179771 read=76030 written=189
                     ->  Seq Scan on orders  (cost=0.00..407300.59 rows=15149959 width=4) (actual time=0.021..6272.001 rows=15015000 loops=1)
                           Buffers: shared hit=179771 read=76030 written=189
 Planning time: 3.850 ms
 Execution time: 16432.862 ms
(34 rows)

COMMIT;
COMMIT