#44579 [Opn->Bgs]: reading non-existing value from multidimentional array
ID: 44579
Updated by: jani@php.net
Reported By: alex at raintree dot ee
-Status: Open
+Status: Bogus
Bug Type: Arrays related
Operating System: Windows Server 2003
PHP Version: 5.2CVS-2008-03-31 (snap)
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Previous Comments:
------------------------------------------------------------------------
[2008-03-31 12:47:14] alex at raintree dot ee
Description:
------------
Noticed serious performance issues while reading non-existing values
from multi-dimensional array.
Adding ISSET() check before the array read makes the script at least 3
times faster.
However the main concern is that there are lots of non-optimized
scripts that do not have ISSET() around multi-dimensional arrays.
Reproduce code:
---------------
error_reporting(0);
$start = date('H:m:s');
$myArr = array('a');
$test = 'a';
// performance killer loop
for($i = 0; $i < 1000000; $i++)
if ($myArr[$test][$fieldName] == 5);
/* optimized code
if (isset($myArr[$test][$fieldName]) && $myArr[$test][$fieldName] ==
5) */
$end = date('H:m:s');
echo $start . ' ' . $end;
Expected result:
----------------
I expect the code with ISSET (commented out) run close to as fast as
the code without ISSET.
Actual result:
--------------
Serious performance difference while running code that has ISSET()
around multi-dimensional array read vs. code without ISSET().
------------------------------------------------------------------------
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