Hi! > From what I've gathered thus far, it is impossible to do without copying the > non-persistent memory into persistent memory, and then back again. I'm > assuming this is because all the memory associated with PHP variables use > emalloc, which places it onto a stack that is disposed of at the end of the > request.
The stack part is wrong, emalloc does not use stack, but the general sense of it is correct - all memory allocated by emalloc is freed at the end of the request, so anything you would want to preserve would have to be copied to some other memory area. > 2 - Modify the Zend engine to flag objects/zvals as persistent so they > aren¹t thrown away until the process ends. The problem with that is that these variables can contain references to other variables and other things (like class in object, etc.) that will be freed, so the data will point to freed memory. Unless the variable is a simple scalar or you do not allow associating it with any other variables in any way you would have this problem. If it's a simple scalar, you can do better by using existing caches. Not allowing associations with other variables means there's not much reason for this thing to actually be a PHP variable. > I've been able to do it somewhat with string zvals, but objects are a > different story (given that a zval contains a handle index referring an > entry in a bucket). The "goal", at least with objects, is the objects > doesn't destruct until the end of the process. With copying memory it looks With objects you have a problem - do you also mean to keep the class? What about the methods code? If you intend to keep all this in memory - and remember you'd also have to guard all of it so no "local" variable gets anywhere into any of object's properties, or sub-values of these properties - I'm not sure you'd do better than serializing. > At this point I feel light a mad scientist. I'm hoping to gain some insight > on how this might be done properly with PHP 5.3/5.4 (or just 5.4) - even if > it involves modifying the Zend engine. Have you guys had any recent > discussions about doing this? Doing it is much harder than you think, since all structures in Zend Engine are assumed to be temporary and you'd need to copy a lot of stuff to make your object work. I wouldn't really advise it. -- Stanislav Malyshev, Software Architect SugarCRM: http://www.sugarcrm.com/ (408)454-6900 ext. 227 -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
