Hi, On Tue, Aug 9, 2011 at 14:22, Arvids Godjuks <arvids.godj...@gmail.com>wrote:
> I have mixed feelings about this proposal - from one point it's quite > neat - ability to mark circular references for the memory manager so > it can free them sounds very delicious, especially for some cases. I > had run into my own bunch of problems with memory in PHP in the past > and right now I'm running a daemon written in PHP in production on > 5.3.6. Careful construction and knowledge that circular references > actually do harm I did add safeguards that actually clean up the > objects in recursive manner (and objects have internal flags that > cleanup has been initiated - that way I make sure I cleanup the same > object only once). That sort of planing at the design stage makes it > far more friendly with memory, so it doesn't mean that PHP should have > soft references. > > My opinion is that if this can be done without using significant > resources and will not have major issues while implementing - it can > be added, otherwise just skip it - better off fixing bugs and > optimizing :) > Weak references have been implemented in a PECL extension since weeks now: http://php.net/weakref and/or http://pecl.php.net/weakref It feels like you're beating up a dead horse here. A discussion for bundling it might occur in the future, but given the feedbacks PECL might very well be the right place for it. Best, > > 2011/8/6 Lars Schultz <lars.schu...@toolpark.com>: > > Am 06.08.2011 02:14, schrieb Hannes Landeholm: > >> > >> Yeah I think there's a lot of misunderstandings going on with weak/soft > >> references and how the garbage collector works. Weak/soft references is > >> not > >> some kind of solution to the cyclic reference problem. The GC takes care > >> of > >> that already. You can use whatever OOP patterns with whatever reference > >> graphs you like Lars, the GC will free the entire structure as soon as > the > >> cyclic collector runs after you are not referencing it anymore. You > might > >> have become a bit confused with my last post where I explained how one > >> could > >> theoretically hack together a soft reference implementation by using > weak > >> references and some properties of cyclic collection. Also property > access > >> performance is off-topic. > > > > I did not misunderstand how weak/soft-references or php's new GC works. > > > > Having a GC collect circular references is neat, but if I remember > > correctly, collecting them (which is why there are other, faster methods > but > > which require more memory) is neither simple nor fast (whatever that > means) > > so...if I can assist the GC by clearly stating that my child-objects may > be > > collected as soon as they and their parent are not referenced from > userland > > anymore thus not requiring the GC and thus freeing memory as soon as > > possible,...seems like an optimization worth thinking of. Especially if I > > tend to have vast structures with hundreds of objects. > > > > In 5.2 (we can't move our project to 5.3 yet because of a BC issue) i had > to > > manually clear those cycles before dropping the last userland reference > to > > the tree of objects because otherwise I'd run into memory problems when > > processing alot of those trees. > > > > > > -- > > PHP Internals - PHP Runtime Development Mailing List > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > > -- Etienne Kneuss http://www.colder.ch
