#18829 [Opn]: array_pop, array_shift, array_push... functions very slow with large arrays
| From: | jean-charles dot rogez at devoteam dot com | Date: | Fri, 09 Aug 2002 11:29:26 +0000 |
| Subject: | #18829 [Opn]: array_pop, array_shift, array_push... functions very slow with large arrays | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-16379@lists.php.net to get a copy of this message | ||
ID: 18829
User updated by: jean-charles.rogez@devoteam.com
Reported By: jean-charles.rogez@devoteam.com
Status: Open
Bug Type: Arrays related
Operating System: Linux RedHat 7.1
PHP Version: 4.2.2
New Comment:
Oops ! I forgot the end of the script
Add
while ($ITER-- > 0) {
$result = test_lists();
}
print "$result\n";
?>
In the previous comment, N meant ITER. (ITER = 50)
Previous Comments:
------------------------------------------------------------------------
[2002-08-09 07:22:28] jean-charles.rogez@devoteam.com
The following program takes a very long time to execute.
On the same machine (P4 1.5GHz), under the same conditions, with N=50,
PHP needs 87m30s !?!! The same program written in PERL 5.6 needs only
2.415s and in python 2.1.2 3.273s ! array_pop and array_push functions
seems to be extremelly slow with large arrays. This problem has been
detected on PHP 4.0.6 and is still present in 4.2.2.
4.2.2 was compiled with the default settings (configure without
arguments).
<?php
function test_lists() {
global $size;
# create a list of integers (Li1) from 1 to SIZE
$Li1 = array();
$Li1 = array_pad($Li1, $size, 0);
# copy the list to Li2 (not by individual items)
$Li2 = $Li1;
$Li3 = array();
# remove each individual item from left side of Li2 and
# append to right side of Li3 (preserving order)
while ($Li2) {
$Li3[] = array_shift($Li2);
}
# Li2 must now be empty
# remove each individual item from right side of Li3 and
# append to right side of Li2 (reversing list)
while ($Li3) {
$Li2[] = array_pop($Li3);
}
# Li3 must now be empty
# reverse Li1 in place
$Li1 = array_reverse($Li1);
# check that first item is now SIZE
if ($Li1[0] != $SIZE) return(0);
# compare Li1 and Li2 for equality
$len1 = count($Li1);
$len2 = count($Li2);
$lists_equal = ($len1 == $len2);
if (! $lists_equal) return(0);
for ($i=0; $i<$len1; $i++) {
if ($Li1[$i] != $Li2[$i]) {
$lists_equal = 0;
break;
}
}
if (! $lists_equal) return(0);
# return the length of the list
return($len1);
}
$size = 10000;
$ITER = $argv[1];
if ($ITER < 1) $ITER = 1;
$result = 0;
?>
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Edit this bug report at http://bugs.php.net/?id=18829&edit=1