#6608 [Com]: sizeof($array) extremly slow in loop. 90% cpu util
| From: | benji at daystream dot com | Date: | Sat, 01 Mar 2003 18:51:00 +0000 |
| Subject: | #6608 [Com]: sizeof($array) extremly slow in loop. 90% cpu util | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-34586@lists.php.net to get a copy of this message | ||
ID: 6608
Comment by: benji at daystream dot com
Reported By: mledet at spirenet dot com
Status: Closed
Bug Type: Performance problem
Operating System: Linux 2.2.16
PHP Version: 4.0.2
New Comment:
Please reopen this issue. It still exists in version 4.3.0. I'm running
on OSX. The performance with a large array that uses sizeof() in a loop
is very poor. It's abut 50X slower than it should be.
The following takes 8-10 seconds:
for ($i=1;$i<=sizeof($spell);$i++) {
$sentence=str_replace($spell[$i][0],$spell[$i][1],$sentence);
}
Whereas the following takes only .18 seconds:
$end=sizeof($spell);
for ($i=1;$i<=$end;$i++) {
$sentence=str_replace($spell[$i][0],$spell[$i][1],$sentence);
}
Previous Comments:
------------------------------------------------------------------------
[2001-05-10 05:55:09] sniper@php.net
No feedback. I problem exists with 4.0.5, reopen.
------------------------------------------------------------------------
[2001-04-10 10:12:23] sbergmann@php.net
Could you please test your script with either the PHP 4.0.4pl1 release,
the latest PHP 4.0.5 RC or a current CVS snapshot from
http://snaps.php.net/? Thanks.
------------------------------------------------------------------------
[2000-09-07 13:01:24] mledet at spirenet dot com
The following code performed well under 3.0.16.
for ($i=0; $i < sizeof($teacherarray); $i++) {
$a=$teacher_array[$i];
if ($a->teacher_id==$teacher_id) {
break;
}
}
However, under php 4.0.2 it is extrememly slow and causes cpu util for
the httpd process to hit 90%. $teacherarray is not being modified
during the loop so the condition isn't changing.
BTW: Changing to the following code works ok.
$numteachers = sizeof($teacherarray);
for ($i=0; $i < $numteachers; $i++) {
$a=$teacher_array[$i];
if ($a->teacher_id==$teacher_id) {
break;
}
}
Either the sizeof function has had a serious decrease in its speed or
something is awry..
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Edit this bug report at http://bugs.php.net/?id=6608&edit=1