------------------ 原始邮件 ------------------ 发件人: "Anatol Belski";<[email protected]>; 发送时间: 2014年8月24日(星期天) 上午9:25 收件人: "China 陈毓端"<[email protected]>; 抄送: "'Pierre Joye'"<[email protected]>; "'pecl-dev'"<[email protected]>; 主题: RE: [PECL-DEV] I want to publish my PHPExtension in PECL
Hi, > -----Original Message----- > From: China 陈毓端 [mailto:[email protected]] > Sent: Wednesday, August 20, 2014 6:01 AM > To: Anatol Belski > Cc: Anatol Belski; Pierre Joye; pecl-dev > Subject: [PECL-DEV] I want to publish my PHPExtension in PECL > > ------------------ 原始邮件 ------------------ > 发件人: "Anatol Belski";<[email protected]>; > 发送时间: 2014年8月9日(星期六) 凌晨2:50 > 收件人: "China 陈毓端"<[email protected]>; > 抄送: "Anatol Belski"<[email protected]>; "Pierre > Joye"<[email protected]>; "pecl-dev"<[email protected]>; > 主题: Re: [PECL-DEV]回复： [PECL-DEV] I want to publish my PHPExtension in > PECL > > > > On Fri, August 8, 2014 18:24, China 陈毓端 wrote: > >> libdhfs is thread safe. > >> > >> > >> Concurrency and Hadoop FS "handles" > >> The Hadoop FS implementation includes a FS handle cache which caches > >> based on the URI of the namenode along with the user connecting. So, > >> all calls to hdfsConnect will return the same handle but calls to > >> hdfsConnectAsUser with different users will return different handles. > >> But, since HDFS client > >> handles are completely thread safe, this has no bearing on concurrency. > >> > >> > >> Concurrency and libhdfs/JNI > >> The libhdfs calls to JNI should always be creating thread local > >> storage, so (in theory), libhdfs should be as thread safe as the > >> underlying calls to the Hadoop FS. > >> > >> > >> > >> http://hadoop.apache.org/docs/r2.2.0/hadoop-project-dist/hadoop-hdfs/ > >> Li > >> bH dfs.html > >> > > > >> With TS builds PHP doesn't create thread local storage but passes the > >> thread ID to each function that requires it, as defined here > >> http://lxr.php.net/xref/PHP_5_4/TSRM/TSRM.h#165 (all the TSRMLS_* > >> stuff). Furthermore thread safety in PHP means that every request is > >> served in a separate thread and that is ruled by the correspending SAPI. > >> So the > >> meaning of ZTS in PHP has no relation to the thread safety of some > >> library (as long as you don't need all the PHP structures to be > >> thread safe). A tread safe library can properly work within a > >> multi-threaded program, that's it. Which means it also can work > >> within a single threaded program. > > > >> If libhdfs is theadsafe, it should be able to handle multiple > >> hdfsConnect() and others in a TS and NTS binaries. Looking at the > >> example from the apache doc, that's a single threaded program (so > >> effectively a NTS PHP as analogue). > >> > > > >> But what I can see from the code, like here > >> https://github.com/yuduanchen/phdfs/blob/master/phdfs.c#L28 - your > >> implementation in PHP is currently not thread safe. The globally > >> defined struct php_hdfs_hanele is accessed directly in every method > >> of the phdfs class. In the NTS build that means it works as a > >> singleton pattern, one cannot simultaneously create two objects > >> connecting to different hadoop instances. In the TS build it's even > >> worse as that struct will be concurrently changed from every request. > > > >> To properly implement the phdfs class, you should use the > >> create_object callback provided by the zend_class_entry struct > >> (you'll also need to define a handler for object destroying). Please > >> take a look at this for example > >> http://lxr.php.net/xref/PECL/xmldiff/xmldiff.cpp#214 or any other > >> core/pecl extension implementing an internal class. > >> > > > > > > I have made some changes > > > > > > >Yeah, now it's thread safe. But still it's a singleton, as despite port > >and host are incapsulated into the class, the internal fs handle is > >global for all the class instances. If that's what is needed, that's > >fine. But I guess it's not so. > > >Otherwise the create_object callback is vital to utilize. You could > >then move the port and host initialization into the constructor, or > >additionally implement the read_property/write_property callback for > >the current syntax to stay, or implement setters/getters. Anyway the > >fs, port and host members would move into an internal object struct. > >Another good example on how to do this > >http://lxr.php.net/xref/PHP_5_4/ext/dom/php_dom.c#762 > > > > Hello, > I've made changes. >Looks like now you're safe - thread safe, everything is incapsulated into the >object. >Regards >Anatol Are there any questions? What time can be income to pecl?
