[RESOLVED] session_start() intermittently fails on the same page

ppowell

I am using session_start() on index.php and for some reason sometimes it'll fail. No warnings, no errors, no notices, not even after prepending error_reporting(E_ALL) and ini_set('display_errors', TRUE) before session_start() do I see anything, it just plain dies.

I used LiveHTTPHeaders to verify that I am getting a 200 OK response, thus everything seems OK except that it's dying on session_start().

Sometimes.

I'll go and refresh the page and then POOF everything is just fine, the page delivers. I'll refresh a few more times to test and then after 2 - 3 times it fails again. Then works again. Then fails again. On and on intermittently.

I can't find anything online that addresses such an unusual problem, but what on earth do I do?

Phil

ppowell

Update: I was finally able to produce the fatal error:

Fatal error: session_start(): Failed to initialize storage module: user (path: /var/lib/php/session) in /var/www/html/tools/ivc/include/code_header_script.inc.php on line 21

Phil

suntra

Google is your friend !

http://www.google.ca/search?hl=en&q=Fatal+error%3A+session_start%28%29%3A+Failed+to+initialize+storage+module%3A&btnG=Recherche+Google&meta=

ppowell

Sorry, but Google is "not a good friend". The value of session.save_handler is "files", whether I set it via ini_set(), .htaccess or I don't set it at all (it's that way in php.ini)

Phil

ppowell

Actually Google IS my friend after all; it's a PHP bug! http://bugs.php.net/bug.php?id=25876

MarkR

This PHP bug is not confirmed as a bug.

Regardless of what you have in php.ini, the behaviour of session_start() is governed by the value of the settings at the time you call it.

Your application may be setting a different handler before calling session_start().

Without any code we cannot possibly know.

If this is in the context of a larger application, try to reduce it to the minimum required to reproduce the issue reliably.

On further reading of the bug report, although the PHP team haven't confirmed it, a lot of people have experienced it.

My guess is that this only happens on shared hosting (Ouch!) and is somehow caused by session incorrectly remembering its ini setting between requests. ini_set('session.handler', 'files') seems to fix it for most people.

Can you reproduce this in your dev environment?

Mark

ppowell

following is the code, literally stripped down to the barebones:

<?
 error_reporting(E_ALL);
 ini_set('display_errors', true);
 session_cache_handler();
 session_start();
 phpinfo();
?>

That is literally all there is now to index.php. Sometimes phpinfo() appears, sometimes nothing appears whatsoever except the fatal error that I mentioned earlier.

I do not see how I could be doing anything to session_start() as there is no call to session_set_save_handler() taking place.

Phil

ppowell

I somehow found a fix, based upon the fact that this issue is listed as an open PHP bug in http://bugs.php.net/bug.php?id=25876

I simply changed my code to:

<?
  error_reporting(E_ALL & ~E_NOTICE); // YOU MUST ADD "~E_NOTICE" ELSE YOU WILL POSSIBLY THROW NOTICES THAT WILL CAUSE session_cache_handler() TO THROW A WARNING AND IT GOES FROM THERE
  ini_set('display_errors', true);
  ini_set('session.save_handler', 'files'); // THIS FIXES THE PROBLEM EVEN IF ini_get('session.save_handler') WOULD RETURN 'files' BEFOREHAND
  session_cache_handler();
  session_start();
  phpinfo();
?>

Apparently you have to "force" session.save_handler" to becomes "files" even though it will be listed as such within php.ini (revealed also within both phpinfo() and ini_get()), that and to do a web server restart.

Phil