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
				('15', '14', '12', '25', '29', '33', '26')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('15', '14', '12', '25', '29', '33', '26')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695874.74..695874.74 rows=3 width=20) (actual time=9505.023..9505.023 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=178323 read=149299 dirtied=253 written=160
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52900.74..52900.75 rows=1 width=4) (actual time=703.912..703.912 rows=1 loops=1)
           Buffers: shared hit=11 read=36332 written=130
           ->  Bitmap Heap Scan on customer customer_1  (cost=6645.96..51946.24 rows=381801 width=4) (actual time=105.051..631.622 rows=382156 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,12,25,29,33,26}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=11 read=36332 written=130
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.51 rows=381801 width=0) (actual time=95.768..95.768 rows=382156 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{15,14,12,25,29,33,26}'::text[]))
                       Buffers: shared hit=9 read=1056 written=6
   ->  HashAggregate  (cost=642973.91..642973.96 rows=3 width=20) (actual time=9504.973..9504.974 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=178320 read=149299 dirtied=253 written=160
         ->  Hash Anti Join  (cost=598994.73..642531.95 rows=58929 width=20) (actual time=8894.216..9477.141 rows=63599 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=178320 read=149299 dirtied=253 written=160
               ->  Bitmap Heap Scan on customer  (cost=2909.79..41862.32 rows=139982 width=24) (actual time=769.758..1218.890 rows=190944 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,12,25,29,33,26}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35177
                     Buffers: shared hit=23 read=72045 written=130
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.79 rows=139982 width=0) (actual time=761.038..761.038 rows=190944 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,12,25,29,33,26}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36871 written=130
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=8078.871..8078.871 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=178294 read=77254 dirtied=253 written=30
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.032..4128.338 rows=15015000 loops=1)
                           Buffers: shared hit=178294 read=77254 dirtied=253 written=30
 Planning time: 2.759 ms
 Execution time: 9509.036 ms
(34 rows)

COMMIT;
COMMIT