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
				('10', '29', '26', '25', '19', '31', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('10', '29', '26', '25', '19', '31', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694712.43..694712.43 rows=3 width=20) (actual time=13479.834..13479.834 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=213714 read=113405 dirtied=473 written=65
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52913.49..52913.50 rows=1 width=4) (actual time=690.018..690.018 rows=1 loops=1)
           Buffers: shared hit=22406 read=13935 written=5
           ->  Bitmap Heap Scan on customer customer_1  (cost=6648.67..51958.11 rows=382150 width=4) (actual time=104.606..610.032 rows=381752 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,29,26,25,19,31,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=22406 read=13935 written=5
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6553.14 rows=382150 width=0) (actual time=95.071..95.071 rows=381752 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{10,29,26,25,19,31,17}'::text[]))
                       Buffers: shared hit=7 read=1056 written=1
   ->  HashAggregate  (cost=641798.86..641798.90 rows=3 width=20) (actual time=13479.778..13479.780 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=213711 read=113405 dirtied=473 written=65
         ->  Hash Anti Join  (cost=597813.27..641356.43 rows=58991 width=20) (actual time=13095.072..13459.495 rows=63636 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=213711 read=113405 dirtied=473 written=65
               ->  Bitmap Heap Scan on customer  (cost=2910.94..41866.30 rows=140090 width=24) (actual time=756.690..989.074 rows=190809 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,29,26,25,19,31,17}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35185
                     Buffers: shared hit=57600 read=14472 written=5
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.91 rows=140090 width=0) (actual time=747.326..747.326 rows=190809 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,29,26,25,19,31,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=22415 read=14472 written=5
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=12256.902..12256.902 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=156108 read=98933 dirtied=473 written=60
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.020..6743.451 rows=15015000 loops=1)
                           Buffers: shared hit=156108 read=98933 dirtied=473 written=60
 Planning time: 3.308 ms
 Execution time: 13484.852 ms
(34 rows)

COMMIT;
COMMIT