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
				('26', '11', '28', '33', '34', '31', '25')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('26', '11', '28', '33', '34', '31', '25')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693482.32..693482.33 rows=3 width=20) (actual time=31856.577..31856.578 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=179988 read=146349 dirtied=426 written=21
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52912.65..52912.66 rows=1 width=4) (actual time=1984.418..1984.419 rows=1 loops=1)
           Buffers: shared hit=7257 read=29085
           ->  Bitmap Heap Scan on customer  (cost=6647.64..51957.26 rows=382157 width=4) (actual time=268.965..1856.896 rows=381578 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,11,28,33,34,31,25}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=7257 read=29085
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.10 rows=382157 width=0) (actual time=255.859..255.859 rows=381578 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{26,11,28,33,34,31,25}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=640569.59..640569.64 rows=3 width=20) (actual time=31856.496..31856.499 rows=7 loops=1)
         Buffers: shared hit=179986 read=146349 dirtied=426 written=21
         ->  Hash Anti Join  (cost=596039.42..640125.08 rows=59268 width=20) (actual time=30260.996..31796.256 rows=63545 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=179986 read=146349 dirtied=426 written=21
               ->  Bitmap Heap Scan on customer  (cost=2909.86..41865.27 rows=140092 width=24) (actual time=2104.019..3137.121 rows=190858 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,11,28,33,34,31,25}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=42404 read=29647
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.84 rows=140092 width=0) (actual time=2091.089..2091.089 rows=190858 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,11,28,33,34,31,25}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=7266 read=29624
               ->  Hash  (cost=404880.36..404880.36 rows=15059936 width=4) (actual time=28146.904..28146.904 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=137579 read=116702 dirtied=426 written=21
                     ->  Seq Scan on orders  (cost=0.00..404880.36 rows=15059936 width=4) (actual time=0.036..16494.017 rows=15015000 loops=1)
                           Buffers: shared hit=137579 read=116702 dirtied=426 written=21
 Total runtime: 32028.157 ms
(30 rows)

COMMIT;
COMMIT