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', '25', '22', '10', '32', '14', '33')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '25', '22', '10', '32', '14', '33')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694130.99..694130.99 rows=3 width=20) (actual time=11523.634..11523.634 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=207006 read=119827 written=65
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52933.87..52933.88 rows=1 width=4) (actual time=752.948..752.948 rows=1 loops=1)
           Buffers: shared hit=13 read=36328
           ->  Bitmap Heap Scan on customer customer_1  (cost=6653.01..51977.10 rows=382708 width=4) (actual time=92.173..680.863 rows=381856 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,25,22,10,32,14,33}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=13 read=36328
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6557.34 rows=382708 width=0) (actual time=83.397..83.397 rows=381856 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,25,22,10,32,14,33}'::text[]))
                       Buffers: shared hit=10 read=1053
   ->  HashAggregate  (cost=641197.04..641197.08 rows=3 width=20) (actual time=11523.580..11523.584 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=207003 read=119827 written=65
         ->  Hash Anti Join  (cost=597220.85..640750.59 rows=59526 width=20) (actual time=10833.184..11498.796 rows=63573 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=207003 read=119827 written=65
               ->  Bitmap Heap Scan on customer  (cost=2911.01..41866.58 rows=140098 width=24) (actual time=811.586..1315.692 rows=190723 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,25,22,10,32,14,33}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35153
                     Buffers: shared hit=27 read=72013 written=15
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.98 rows=140098 width=0) (actual time=803.129..803.129 rows=190723 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,25,22,10,32,14,33}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25 read=36862
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=9515.417..9515.417 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=206973 read=47814 written=50
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.020..4677.313 rows=15015000 loops=1)
                           Buffers: shared hit=206973 read=47814 written=50
 Planning time: 2.843 ms
 Execution time: 11541.705 ms
(34 rows)

COMMIT;
COMMIT