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
				('33', '16', '32', '10', '19', '12', '18')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('33', '16', '32', '10', '19', '12', '18')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698288.66..698288.67 rows=3 width=20) (actual time=10363.084..10363.085 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=323866 read=4722 dirtied=243 written=139
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52971.84..52971.85 rows=1 width=4) (actual time=488.778..488.779 rows=1 loops=1)
           Buffers: shared hit=35283 read=1061 written=96
           ->  Bitmap Heap Scan on customer customer_1  (cost=6679.94..52014.11 rows=383092 width=4) (actual time=98.563..413.369 rows=382695 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,32,10,19,12,18}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35277
                 Buffers: shared hit=35283 read=1061 written=96
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6584.17 rows=383092 width=0) (actual time=89.308..89.308 rows=382695 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{33,16,32,10,19,12,18}'::text[]))
                       Buffers: shared hit=9 read=1058 written=96
   ->  HashAggregate  (cost=645316.74..645316.78 rows=3 width=20) (actual time=10363.025..10363.026 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=323863 read=4722 dirtied=243 written=139
         ->  Hash Anti Join  (cost=601298.07..644875.00 rows=58899 width=20) (actual time=9984.703..10341.579 rows=63672 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=323863 read=4722 dirtied=243 written=139
               ->  Bitmap Heap Scan on customer  (cost=2943.53..41910.65 rows=140538 width=24) (actual time=565.539..789.564 rows=190994 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,32,10,19,12,18}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35170
                     Buffers: shared hit=68147 read=3914 written=139
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2908.39 rows=140538 width=0) (actual time=554.991..554.991 rows=190994 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,32,10,19,12,18}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35293 read=1598 written=139
               ->  Hash  (cost=408447.02..408447.02 rows=15192602 width=4) (actual time=9190.569..9190.569 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=255713 read=808 dirtied=243
                     ->  Seq Scan on orders  (cost=0.00..408447.02 rows=15192602 width=4) (actual time=0.020..4295.459 rows=15000000 loops=1)
                           Buffers: shared hit=255713 read=808 dirtied=243
 Planning time: 2.661 ms
 Execution time: 10380.012 ms
(34 rows)

COMMIT;
COMMIT