ID: 35258
Updated by: [EMAIL PROTECTED]
Reported By: [EMAIL PROTECTED]
-Status: Open
+Status: Closed
Bug Type: Documentation problem
Operating System: Linux
PHP Version: 4.4.1
New Comment:
This bug has been fixed in the documentation's XML sources. Since the
online and downloadable versions of the documentation need some time
to get updated, we would like to ask you to be a bit patient.
Thank you for the report, and for helping us make our documentation
better.
Previous Comments:
------------------------------------------------------------------------
[2006-02-05 21:20:35] [EMAIL PROTECTED]
I think PHP users definitely want to now about this. Why should they
not want to know? I think it's important to know that the preg_*
functions cache the regular expression while ereg don't. Because that
means that preg* over ereg* consumes memory in the long term, which, as
I i've seen it in real live, became an issue. Since I had this
spontanous memory problems I consulted the preg* manual page but
nowwhere it wasn't mentioned and I hat to find it out myself which took
some time.
Why not shorten other peoples time by documenting it?
------------------------------------------------------------------------
[2005-12-13 20:01:22] [EMAIL PROTECTED]
The pcre extension API (used by preg_*() functions, the new filter
extension,..) cache compiled regexes, but since PHP xx (I don't
remember the version.. :) ), that cache has a limit.
So memory usage won't grow indefinetely, it will "just" cache 4096
regexes (by default).
I don't think this should be documented. PHP users don't really want to
know about internal stuff.
------------------------------------------------------------------------
[2005-12-13 11:45:34] [EMAIL PROTECTED]
No doubt. However, the ereg* family of functions does not consume
memory in the way the preg* family of functions does. So this is
actually a documentation problem it seems, re-cateogrizing.
------------------------------------------------------------------------
[2005-12-13 10:45:03] [EMAIL PROTECTED]
This is the same issue as all the other "PHP does not release memory"
reports. The memory reserved is never released during script run. It's
released during shutdown.
------------------------------------------------------------------------
[2005-12-13 09:53:55] [EMAIL PROTECTED]
Your answer is interesting. If I take your example and insert another
var_dump() before the unset() command, like this:
<?php
var_dump(memory_get_usage());
$input = str_pad("", 50000, "foo");
var_dump(memory_get_usage());
$input = preg_replace(";foo;", "", $input);
var_dump(memory_get_usage());
unset($input); // <------------ !!
var_dump(memory_get_usage());
I get these numbers:
$ php test.php
int(15496)
int(65600)
int(115632)
int(15624)
However, there is not benefit in unsetting the return value from
preg_replace else I could remove the call to it anyway.
But maybe the example was bad. Take for example, I want to replace
'foo' with 'bar':
<?php
var_dump(memory_get_usage());
$input = str_pad("", 50000, "foo");
var_dump(memory_get_usage());
$input = preg_replace(";foo;", "bar", $input);
var_dump(memory_get_usage());
$ php test.php
int(15208)
int(65312)
int(115352)
If I want to further work with the value I have no way of saving memory
(I can't really unset the value when I need it).
I also don't quite understand the statement "memory usage doesn't
depend on the length of the data". The numbers are certainly different
when I use small strings.
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/35258
--
Edit this bug report at http://bugs.php.net/?id=35258&edit=1
