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', '24', '34', '10', '30', '33', '18')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '24', '34', '10', '30', '33', '18')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694039.64..694039.64 rows=3 width=20) (actual time=11476.989..11476.990 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=222625 read=104222 dirtied=1 written=2985
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52867.02..52867.03 rows=1 width=4) (actual time=564.759..564.759 rows=1 loops=1)
           Buffers: shared hit=35285 read=1056
           ->  Bitmap Heap Scan on customer customer_1  (cost=6638.80..51914.82 rows=380877 width=4) (actual time=118.239..482.058 rows=381343 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,24,34,10,30,33,18}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35285 read=1056
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6543.58 rows=380877 width=0) (actual time=108.996..108.996 rows=381343 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,24,34,10,30,33,18}'::text[]))
                       Buffers: shared hit=10 read=1053
   ->  HashAggregate  (cost=641172.54..641172.59 rows=3 width=20) (actual time=11476.921..11476.922 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=222622 read=104222 dirtied=1 written=2985
         ->  Hash Anti Join  (cost=597215.97..640731.59 rows=58794 width=20) (actual time=11093.201..11455.214 rows=63860 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=222622 read=104222 dirtied=1 written=2985
               ->  Bitmap Heap Scan on customer  (cost=2906.13..41849.23 rows=139623 width=24) (actual time=629.982..861.127 rows=190425 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,24,34,10,30,33,18}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35167
                     Buffers: shared hit=70004 read=2050
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.22 rows=139623 width=0) (actual time=620.809..620.809 rows=190425 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,24,34,10,30,33,18}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35295 read=1592
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=10371.549..10371.549 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=152615 read=102172 dirtied=1 written=2985
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.018..5042.696 rows=15000000 loops=1)
                           Buffers: shared hit=152615 read=102172 dirtied=1 written=2985
 Planning time: 3.710 ms
 Execution time: 11482.017 ms
(34 rows)

COMMIT;
COMMIT