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
				('11', '17', '19', '24', '25', '27', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '17', '19', '24', '25', '27', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697629.73..697629.74 rows=3 width=20) (actual time=10004.091..10004.092 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=285841 read=42520 dirtied=219 written=233
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52891.77..52891.78 rows=1 width=4) (actual time=422.344..422.344 rows=1 loops=1)
           Buffers: shared hit=35286 read=1053 written=128
           ->  Bitmap Heap Scan on customer customer_1  (cost=6644.06..51937.88 rows=381555 width=4) (actual time=99.645..351.232 rows=381023 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,17,19,24,25,27,30}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35286 read=1053 written=128
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6548.67 rows=381555 width=0) (actual time=90.536..90.536 rows=381023 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,17,19,24,25,27,30}'::text[]))
                       Buffers: shared hit=8 read=1053 written=128
   ->  HashAggregate  (cost=644737.88..644737.92 rows=3 width=20) (actual time=10004.047..10004.050 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=285838 read=42520 dirtied=219 written=233
         ->  Hash Anti Join  (cost=600764.28..644296.20 rows=58891 width=20) (actual time=9341.788..9975.579 rows=63599 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=285838 read=42520 dirtied=219 written=233
               ->  Bitmap Heap Scan on customer  (cost=2908.93..41859.09 rows=139892 width=24) (actual time=488.228..967.661 rows=190196 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,17,19,24,25,27,30}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35165
                     Buffers: shared hit=35298 read=36750 written=222
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.95 rows=139892 width=0) (actual time=479.536..479.536 rows=190196 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,17,19,24,25,27,30}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35296 read=1587 written=187
               ->  Hash  (cost=408106.27..408106.27 rows=15179927 width=4) (actual time=8773.677..8773.677 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=250537 read=5770 dirtied=219 written=11
                     ->  Seq Scan on orders  (cost=0.00..408106.27 rows=15179927 width=4) (actual time=0.015..3592.217 rows=15015000 loops=1)
                           Buffers: shared hit=250537 read=5770 dirtied=219 written=11
 Planning time: 2.215 ms
 Execution time: 10019.582 ms
(34 rows)

COMMIT;
COMMIT