Edit report at https://bugs.php.net/bug.php?id=37106&edit=1
ID: 37106
Comment by: scott dot baker at gmail dot com
Reported by: webmaster at polskabizuteria dot pl
Summary: uniqid() without more_entropy extremally slow
Status: Not a bug
Type: Bug
Package: Performance problem
Operating System: *
PHP Version: *
Block user comment: N
Private report: N
New Comment:
$loop = 10000;
print "uniqid('') x $loop = " . bench('gen_uniqid',$loop) . " seconds<br />";
print "uniqid('',true) x $loop = " . bench('gen_uniqid_entropy',$loop) . "
seconds<br />";
function gen_uniqid() {
return uniqid('');
}
function gen_uniqid_entropy() {
return uniqid('',true);
}
function bench($func,$times) {
$start = microtime(1);
for ($i = 0; $i < $times; $i++) {
call_user_func($func);
}
$end = microtime(1);
$ret = sprintf("%0.4f",$end - $start);
return $ret;
}
------------------------------------------------------
uniqid('') x 10000 = 1.5876 seconds
uniqid('',true) x 10000 = 0.0329 seconds
Telling uniqid() to use more_entropy is MORE than 48 times faster
Previous Comments:
------------------------------------------------------------------------
[2006-05-28 12:34:05] [email protected]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php
uniqid() is meant to give you a certrain id distribuion that is not predicable.
That is uniqid() must neither generate two identical ids nor have a constant or
in any way predictable difference between two calls. To ensure this we use
usleep() internally to either force a thread (windows) or process (*nix)
switch. On some systems the operating system has a slow implementation of this.
However distrubition this much more important than the security risks implied.
------------------------------------------------------------------------
[2006-04-17 14:52:45] webmaster at polskabizuteria dot pl
Description:
------------
Uniquid() without second parameter (more_entropy) set as true is extremaly slow
(approx 500 times)
Reproduce code:
---------------
/* SLOW */
uniqid();
uniqid("");
uniqid("",false);
/* FAST */
uniqid("",true);
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=37106&edit=1
