Re: [Resin-interest] application variables, j2ee - php, and shared nothing
(this is sorta off topic -- I suggest asking this question at Java Ranch) I think the answer to your question always depends on what it is you're trying to accomplish. I also think there is some cross-cultural confusion, as you can certainly create a shared-nothing Java webapp. yong On Jun 26, 2007, at 7:08 AM, Nathan Nobbe wrote: all, im curious about application variables under the j2ee web application paradigm. are these used frequently in the context of application servers, like resin, or are they regarded as taboo? also, has anyone heard of the shared nothing architecture? how does that pertain, if at all, to the j2ee paradigm? i was discussing application variables w/ some members of php-general and from the sound of it; they are taboo in the php world. can any quercus users shed some light on this conundrum? thanks, -nathan ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
Re: [Resin-interest] application variables, j2ee - php, and shared nothing
im curious about application variables under the j2ee web application paradigm. are these used frequently in the context of application servers, like resin, or are they regarded as taboo? also, has anyone heard of the shared nothing architecture? how does that pertain, if at all, to the j2ee paradigm? i was discussing application variables w/ some members of php-general and from the sound of it; they are taboo in the php world. Application variables are not possible in the php world when using the C implementation. Each php request is served by a different proccess, and those processes cannot share data without using an intermediary like a database, the file system, or a cache server. The processes also cannot share database connections, so connection pooling is not an option, which can be a serious scalability issue. Using the application scope for things like common configuration and caching can be very effective. The cache-coherence problem is a problem if the application requires that the cache have absolutely up to date information in it. Much of the information served on the web can be cached and have some inconsistency for a short period of time. -- Sam ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
Re: [Resin-interest] application variables, j2ee - php, and shared nothing
On Jun 26, 2007, at 6:08 AM, Nathan Nobbe wrote: all, im curious about application variables under the j2ee web application paradigm. are these used frequently in the context of application servers, like resin, or are they regarded as taboo? For the most part, application state (i.e. single-jvm data) is either configuration or caching/pooling. It's not common to put non-cache state on a single JVM because it doesn't scale. also, has anyone heard of the shared nothing architecture? how does that pertain, if at all, to the j2ee paradigm? That article looks misleading for j2ee (and also for php). For many (most?) major sites, the database is the major headache, and that shared database doesn't really count as shared nothing. A major difference between php and j2ee is caching/pool. Php essentially does zero caching on the app server tier, so some larger sites dedicate a separate tier for caching (e.g. dedicated memcache servers.) J2ee tends to cache on the app-server tier itself, which is simpler and more efficient than the separate caching tier. So there is state on each JVM for j2ee, but it's generally cache/ pooling state, not application state. i was discussing application variables w/ some members of php- general and from the sound of it; they are taboo in the php world. Yes, well, it's difficult to cache/share state in php at all, and thread synchronization is essentially non-existent, so it's taboo mostly because the capability doesn't really exist. (Quercus does not share this PHP limitation, by the way. It's entirely possible to use a Java layer for caching/pooling and expose the cached/pooled values to a PHP layer.) -- Scott can any quercus users shed some light on this conundrum? thanks, -nathan ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
