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
				('19', '34', '27', '12', '33', '10', '23')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '34', '27', '12', '33', '10', '23')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694150.68..694150.69 rows=3 width=20) (actual time=9478.328..9478.329 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=253284 read=73570 dirtied=253
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52930.29..52930.30 rows=1 width=4) (actual time=681.137..681.138 rows=1 loops=1)
           Buffers: shared hit=10 read=36331
           ->  Bitmap Heap Scan on customer customer_1  (cost=6652.25..51973.77 rows=382610 width=4) (actual time=96.261..609.493 rows=381748 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,27,12,33,10,23}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35277
                 Buffers: shared hit=10 read=36331
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6556.60 rows=382610 width=0) (actual time=87.486..87.486 rows=381748 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,34,27,12,33,10,23}'::text[]))
                       Buffers: shared hit=8 read=1056
   ->  HashAggregate  (cost=641220.31..641220.36 rows=3 width=20) (actual time=9478.284..9478.285 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=253281 read=73570 dirtied=253
         ->  Hash Anti Join  (cost=597222.71..640777.41 rows=59053 width=20) (actual time=8863.696..9450.338 rows=63463 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=253281 read=73570 dirtied=253
               ->  Bitmap Heap Scan on customer  (cost=2912.87..41873.17 rows=140278 width=24) (actual time=748.007..1205.921 rows=190546 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,27,12,33,10,23}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35175
                     Buffers: shared hit=21 read=72040
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2877.80 rows=140278 width=0) (actual time=739.216..739.216 rows=190546 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,34,27,12,33,10,23}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=19 read=36867
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=8046.147..8046.147 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=253257 read=1530 dirtied=253
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.015..3434.865 rows=15015000 loops=1)
                           Buffers: shared hit=253257 read=1530 dirtied=253
 Planning time: 2.481 ms
 Execution time: 9482.098 ms
(34 rows)

COMMIT;
COMMIT