Sessions by default will use the file system to store session data. Using the file system on a site that utilizes sessions moderately can be negative as far as performance goes.
Using shared memory simply means that session data is now stored in shared memory. Shared memory is a bit more efficient than using the file system. Where session data is stored is supposed to be sort of black box and transparent to the actual use of sessions. You can also define a group of custom session handling functions to use any device your mind can imagine for session storage. Anything PHP can easily connect to (Java, RDBMS, ...) the sky is the limit. Take a look at session_set_save_handler (for custom session handling routines). Once you get your session save handler working it is transparent to the use of sessions. If your having performance troubles with sessions using the file system, shared memory may be the best way to go. Take a look at this page http://www.php.net/manual/en/ref.session.php To actually use shared memory you must modify the option session.save_handler in the php.ini file. Thanks Jeremy Allen -----Original Message----- From: Mark [mailto:[EMAIL PROTECTED]] Sent: Friday, December 14, 2001 10:38 AM To: [EMAIL PROTECTED] Subject: [PHP] Session storage and the --with-mm option I'm trying to cut down on the amount of memory that my apache proceeses use, I've noticed that when I have the --with-mm option set when I configure and compile PHP that the apache process goes up by about 40MB or more on the process table: USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 23102 0.0 2.5 54588 12972 ? S Dec11 0:13 /usr/sbin/httpd nobody 11242 0.0 2.7 55040 14408 ? S Dec13 0:16 /usr/sbin/httpd nobody 11244 0.0 2.7 55076 14216 ? S Dec13 0:16 /usr/sbin/httpd .... I understand that not each process is using up that much ram, but I'd still like to cut down the usage since without having --with-mm enabled makes the processes more like this: USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 29415 0.0 0.7 13988 5844 ? S Dec13 0:02 /usr/sbin/httpd nobody 31719 0.0 0.7 14140 6096 ? S 04:02 0:00 /usr/sbin/httpd nobody 31720 0.0 0.7 14140 6096 ? S 04:02 0:00 /usr/sbin/httpd .... So my question is this. What is the --with-mm option for? The only real documentation I can find about it anywhere is on the PHP site where they have a complete list of configuration options: ---------------------------------------------------------- --with-mm[=DIR] PHP 3: Option not available in PHP 3 PHP 4: Include mm support for session storage ---------------------------------------------------------- Well, that's not really helpful. Does this option affect how sessions work under PHP? I think some of the users on my system have been using sessions successfully without this option. Also, since this gets compiled in the ext/sessions directory, would I be able to compile it as a module that could be loaded into PHP at run time? Any help would be appretiated. Thanks, -- mark.krenz [EMAIL PROTECTED] ____________________________________________________________________________ ___ Their snazzy page and friendly installation process don't make up for damn trickery. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED] _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
