Would it be difficult to just add a "dirty" flag somewhere, so that the session data only gets written out iff a variable has been added, removed, or changed? That way existing php code using sessions would have improved performance. Perhaps combine this idea with Zeev's idea of using 'touch'. I don't see why adding session_readonly() is really necessary, the only possible benefit I see is to avoid the locking issue (with frames etc) on the session file. The locking issue can be solved with session_write_close() though, and in the case of a "dirty" flag, would not even write anything out.
-James On Fri, 16 Aug 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, [EMAIL PROTECTED] wrote: > > > ID: 3793 > > > Updated by: [EMAIL PROTECTED] > > > Reported By: [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] [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] [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] [EMAIL PROTECTED] > > > > > >It seems it never worked under windows. > > >Reopen > > > > > >------------------------------------------------------------------------ > > > > > >[2002-03-31 02:43:13] [EMAIL PROTECTED] > > > > > >The reported errors are still in verson 4.1.2. > > > > > >System: w2k, CGI-version. > > > > > >------------------------------------------------------------------------ > > > > > >[2001-12-16 07:24:47] [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 > > > > > > -- > > PHP Documentation Mailing List (http://www.php.net/) > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > > > -- PHP Development Mailing List <http://www.php.net/> To unsubscribe, visit: http://www.php.net/unsub.php
