note 93670 added to function.session-start

As noted before, if you have multiple concurrent requests from same session, they will serialize based upon session_start()-end of script--unless you call session_write_close. Practically speaking this is not usually an issue and using a single global lock over all session use in a script is arguably the simplest effective mechanism. But be warned that depending on end of script to close the session *will serialize concurrent session requests*. Background "data retrieval" (e.g. AJAX or amfphp/Flex) can fall into this trap easily. Holding the session_write_close until after an expensive operation is likewise problematic. To minimize effects, call session_write_close (aka session_commit) as early as practical (e.g. without introducing race conditions) -- often this possible quite early in the script or otherwise avoid the serialization bottleneck. ---- Server IP: 209.41.74.194 Probable Submitter: 70.132.10.21 ---- Manual Page -- http://www.php.net/manual/en/function.session-start.php Edit -- https://master.php.net/note/edit/93670 Del: integrated -- https://master.php.net/note/delete/93670/integrated Del: useless -- https://master.php.net/note/delete/93670/useless Del: bad code -- https://master.php.net/note/delete/93670/bad+code Del: spam -- https://master.php.net/note/delete/93670/spam Del: non-english -- https://master.php.net/note/delete/93670/non-english Del: in docs -- https://master.php.net/note/delete/93670/in+docs Del: other reasons-- https://master.php.net/note/delete/93670 Reject -- https://master.php.net/note/reject/93670 Search -- https://master.php.net/manage/user-notes.php