Re: Re: PHP 4.1.0 and User-defined Sessions

Jaime Bozza wrote:

I *HAVE* searched the database and there have been similar problems, with the request to try the latest CVS and to produce a short script that duplicates the problem. Since I can't exactly put the CVS version onto a live website (and start having all sorts of other problems) and I can't duplicate the problem consistently on a "non-active testing" site, I don't really have anything else additional to offer except for "Me Too!". My email already stated that I have tried to use --enable-debug and that I'm getting a segfault without any core file whatsoever. The last paragraph explains my attempts on using enable-debug.

This is not practical, but you can try to run apache under gdb. If any segfault happens while you are running apache under gdb, you can get backtrace. BTW, did you try benchmarking tools like ab? You may be able to reproduce problem with benchmark tools. -- Yasuo Ohgaki

Jaime Bozza -----Original Message----- From: Yasuo Ohgaki [mailto:yasuo_ohgaki@yahoo.com] Sent: Wednesday, December 12, 2001 9:04 PM To: php-general@lists.php.net; Jaime Bozza Subject: [PHP] Re: PHP 4.1.0 and User-defined Sessions Search bug database to see if the same problem is reported or not. If you get segfault, buld PHP with --enable-debug and get core file. If it is new, get backtrace as described in bugs.php.net. Submit new bug report. If you found multiple issues, submit bug report separately. There are more comments following. Jaime Bozza wrote:

Hello, I've run into a really intermittent and strange problem with PHP 4.1.0, and before I try and figure out how to send in a bug report that'll get ignored (because I don't have all the data that is expected), I thought I would try here to see if anyone else is having similar problems. Configuration: FreeBSD 4.4-STABLE, PostgreSQL 7.1.3, Apache 1.3.22,

PHP 4.1.0.

So far I don't have problem with Linux 2.4.4/PosrgreSql 7.1.3/Apache 1.3.22/PHP 4.1.0 or 4.2.0-dev

I use PHP Sessions for large parts of our sites. I'm currently using the PostgreSQL Session Handler code from Jon Parise and it had been working pretty much perfectly under PHP 4.0.6. (The only issue was when multiple requests came in with the same session_id at the EXACT same time - AvantGo for instance - But I made some minor modifications to eliminate that problem) Once upgrading to 4.1.0, I started noticing Apache processes segfaulting left and right. (Signal 11's, with the occasional Signal 10) At first I started to think perhaps memory was bad on that particular system. I have 4 servers (running 3-5 separate Apache processes each) and each and every server was giving me the Signal 10/11's. I started looking into it further. I have an auto_prepend for my "application" code that defines the base session variables, config variables, includes the pgsql_session_handler file, etc. All the processing is handled here so that my other pages can just use an array that stores all the session data. That way I can pretty much ignore the backend in any of

my application code.

This setting is similar to mine also.

Once I turned this code off, bingo! No more segfaults! So I started hacking out code there. If I kept all the startup code but eliminated the session commands, it still worked. As soon as I turned

on the session (session_start/session_register), I'd get the segfaults

again.

If you could make *short* script that segfault, attach it to bug report.

If I turned off the pgsql_session_handler and went back to files (the default), I didn't have any problems either. It was just a problem when I was using the pgsql_session_handler.

I'm not sure what your session handler looks like, could try pgsql session handler that can be found at Zend.com's code exchange?

So I then turned off session handling and built my own session functions (quickie, but basically emulate the session functions I needed) that called the SAME pgsql_session_handler code that was being

used by PHP's internal functions. For the past hour I haven't had a single segfault on any of my servers. (Within 5 minutes of turning on

the internal session routines, I would start getting segfaults every minute or so) One other thing I noticed was that I had compiled PHP with the mm shared memory library. Previous to 4.1.0, each Apache process had a size of around 64MB. (Without mm, the size was 4-5MB or so) Once installing 4.1.0, the size went up to >130MB for each process! Since I believe sessions utilize the mm library if it's available, I figure this may be one of the clues. (I never tried using the shared memory style of sessions, so I couldn't tell you if it would segfault there.)

This is strange, mm session module allocates shared memory that is needed. (Description is not fully correct, but almost correct)

Is anyone having any of these problems? Is anyone else using the internal PHP session support with their own session handler (under some of the same conditions I gave above) and having no problems with PHP4.1.0? Please let me know either way. BTW, I never get a core file. I've tried "enable-debug" to get the symbols in there, but without a core file I'm kind of out of luck on tracing. All I can tell you now is that using user-defined handlers for sessions started causing me lots of problems. (As near as I can tell, you need to have some sort of a decent load on your servers - Single client access didn't ever seem to allow me to force the crashes)

You can run httpd under gdb and can take backtrace. Try.

-- Yasuo Ohgaki _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com