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
				('23', '10', '16', '33', '11', '24', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('23', '10', '16', '33', '11', '24', '32')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693406.29..693406.29 rows=3 width=20) (actual time=9544.322..9544.323 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=258207 read=68393 dirtied=1 written=6144
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52833.77..52833.78 rows=1 width=4) (actual time=444.673..444.673 rows=1 loops=1)
           Buffers: shared hit=35441 read=900
           ->  Bitmap Heap Scan on customer customer_1  (cost=6631.75..51883.86 rows=379966 width=4) (actual time=85.517..372.636 rows=381607 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,10,16,33,11,24,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=35441 read=900
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6536.76 rows=379966 width=0) (actual time=77.178..77.178 rows=381607 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{23,10,16,33,11,24,32}'::text[]))
                       Buffers: shared hit=163 read=900
   ->  HashAggregate  (cost=640572.43..640572.48 rows=3 width=20) (actual time=9544.269..9544.270 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=258204 read=68393 dirtied=1 written=6144
         ->  Hash Anti Join  (cost=596623.89..640133.60 rows=58511 width=20) (actual time=9213.634..9523.483 rows=63310 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=258204 read=68393 dirtied=1 written=6144
               ->  Bitmap Heap Scan on customer  (cost=2904.19..41842.31 rows=139433 width=24) (actual time=502.417..703.387 rows=190592 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,10,16,33,11,24,32}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35173
                     Buffers: shared hit=70702 read=1358
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2869.33 rows=139433 width=0) (actual time=494.041..494.041 rows=190592 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,10,16,33,11,24,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35530 read=1357
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=8646.461..8646.461 rows=15000000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658416kB
                     Buffers: shared hit=187499 read=67035 dirtied=1 written=6144
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.019..4493.072 rows=15000000 loops=1)
                           Buffers: shared hit=187499 read=67035 dirtied=1 written=6144
 Planning time: 2.387 ms
 Execution time: 9549.395 ms
(34 rows)

COMMIT;
COMMIT