Re: [PHP-DOC] Re: #3793 [Ana->Opn]: session.gc_maxlifetime does not work From: Zeev Suraski (zeev <email protected>)
Date: 08/17/02

Ok, that makes sense. I like the idea of being able to configure whether
you want to use mtime or atime, so that non atime-compliant filesystems can
still be supported, but we leave the window to support session-readonly in
the future.

Zeev

At 07:37 17/08/2002, Rasmus Lerdorf wrote:
>Ok, thinking a bit more about this.. session_readonly() really should be
>implemented. Imagine a system where you have dynamically generated
>images/flash/pdf or even just a straight framed site. You use sessions to
>pass information around between not only pages, but also to the
>dynamically generated pieces of a page. Having the session backend
>rewrite the same session data many times per request is a waste and if you
>know that you are only going to read in the pdf generator script, for
>example, it would be a good idea to open the session readonly from that
>script. Or not even that fancy. You have a standard login page where you
>pull some data from a database about the user, stick it in a session and
>then the user clicks through the rest of the site. It wouldn't be that
>strange to have hundreds of pages that would need to read that session
>data, but never write to it. With the current implementation we are
>needlessly overwriting the same data on every single request.
>
>If session_readonly() gets implemented then removing atime support for
>filesystems that support that seems like a step in the wrong direction.
>We should perhaps have a modifier on session mod_files which tells it
>whether it should use atime, mtime or perhaps even ctime. Another
>configuration directive sucks, but even if we could detect at runtime that
>atime was not supported, silently falling back to mtime doesn't seem like
>a good idea. I suppose we could change the default to mtime, implement
>session_readonly() and give people the option to switch it to atime.
>
>-Rasmus
>
>On Sat, 17 Aug 2002, Zeev Suraski wrote:
>
> > Just wondering - why are we even using atime? I think lots of filesystems
> > don't support it, but regardless of that - as far as I recall from reading
> > the session code, if a session is opened for reading - it is also going to
> > be rewritten at the end of the session. So, it should be quite safe to
> > check mtime instead of atime.
> > Comments?
> >
> > Zeev
> >
> > At 04:03 17/08/2002, rasmus <email protected> wrote:
> > > ID: 3793
> > > Updated by: rasmus <email protected>
> > > Reported By: kori_mail <email protected>
> > >-Status: Analyzed
> > >+Status: Open
> > >-Bug Type: Session related
> > >+Bug Type: Documentation problem
> > > Operating System: Windows 98
> > > PHP Version: 4 .1.2
> > > New Comment:
> > >
> > >I really don't see anybody with any interest in writing code to make
> > >this work on FAT filesystems. Don't run web servers on crap
> > >filesystems. If you do, write your own session handler. Same goes for
> > >filesystems where file modification timestamps are ignored. Write your
> > >own session handler and manage the garbage collection yourself. We'll
> > >need to document this, of course, so marking this as a documentation
> > >problem.
> > >
> > >
> > >Previous Comments:
> > >------------------------------------------------------------------------
> > >
> > >[2002-07-10 05:10:43] jerome.billet <email protected>
> > >
> > >I've exactly the same problem with Windows 2000, php 4.2.0 and apache
> > >1.3
> > >
> > >------------------------------------------------------------------------
> > >
> > >[2002-03-31 03:49:43] bergmann <email protected>
> > >
> > >After I tried about a week, by just setting the lifetime VERY high
> > >(40000 first), maybe I can give a hint:
> > >
> > >With this very high value it worked, so I tried where exactly was the
> > >critical point. It was somewhat about 32000. Slightly below, all
> > >session files were deleted as described, slightly over not. But then
> > >the error reoccurred with the same value.
> > >
> > >After some tries I found out the following: I set back the time on the
> > >server one hour and it worked again. Here the times and the critical
> > >points:
> > >
> > >At 9:24 local time : 30290
> > >At 10:28 : 34100
> > >
> > >34100-30290=3810, which would be 63.5 minutes when interpretad as
> > >seconds, which is the server's time difference...
> > >
> > >Since 10:28 means 37680 s since 0:00, there seems to be an additional
> > >hour - maybe due to GMT setting (+1) I thought, but it was the
> > >automatic daylight saving (or is it called summer time???) setting.
> > >When turned off, at 9:45 the point was at 35100=9.75 hours...
> > >
> > >I hope that helps... ;-)
> > >
> > >-- mike
> > >
> > >------------------------------------------------------------------------
> > >
> > >[2002-03-31 02:56:29] yohgaki <email protected>
> > >
> > >It seems it never worked under windows.
> > >Reopen
> > >
> > >------------------------------------------------------------------------
> > >
> > >[2002-03-31 02:43:13] bergmann <email protected>
> > >
> > >The reported errors are still in verson 4.1.2.
> > >
> > >System: w2k, CGI-version.
> > >
> > >------------------------------------------------------------------------
> > >
> > >[2001-12-16 07:24:47] sander <email protected>
> > >
> > >No feedback. Closing.
> > >
> > >------------------------------------------------------------------------
> > >
> > >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/3793
> > >
> > >--
> > >Edit this bug report at http://bugs.php.net/?id=3793&edit=1
> >
> >
> > --
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> > 

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