＋设为首页 ＋添加到收藏夹
the oracle internet platform embeds the oracle8i jvm within the oracle8i database and oracle internet application server (ias) as the enterprise java engine for oracle. this article explains oracle8i jvms base architecture, its support for j2ee apis and its latest performance and architecture enhancements.
e-business platform base architecture
in a break from the design of most client java virtual machines, the oracle8i jvm has promoted a session-based architecture in which each user executes within a session. from the users perspective, each session executes java with its own dedicated jvm that has its own containers and its own java global variables and garbage collector. under the covers, sessions are scheduled and run on a dynamically allocated set of processes (or threads on windows/nt) – typically less than 10% of the number of connected users – using oracles multithreaded server (mts). the mts architecture provides robustness, as a replacement process is automatically started by the oracle 8i runtime in the event that process fails. by isolating sessions, this architecture allows parallel and independent processing, memory allocation and garbage collection (see figure 1). on the other hand, sharing of code, metadata, immutable statics and read-only objects across sessions reduces session memory footprint and activation time.session isolation vs sharing 【程序编程相关:XQuery Not Necessari】
the base architecture, the foundation on which a java platforms building blocks are implemented, is typically the vm architecture: memory management, execution environment and so on. as an e-business platform, it should provide robustness, reliability and scalability across all system components. one key question: what makes the oracle8i jvm different from other vms?session-based architecture 【推荐阅读:Forum Systems Integr】
the total number of mts processes required to run tens of thousands of connected users sessions is dynamically adjustable and approximately equals the number of concurrently active sessions (approximately less than 10% of the number of connected users).session iiop 【扩展信息:webMethods Fabric Ga】
java objects held in static variables between calls are, by default, completely private to the users session. the 8i jvm maintains the complete context of each session so that isolation is an implicit part of the system, not one thats enforced by the programming model. session isolation doesnt allow the sharing of user "state" or contexts. oracle8i jvm sessions can share read-only objects across sessions through jndi. this feature is used internally for now to maximize sharing of metadata and will be exposed in the future for use by user programs as well.connectivity
session iiop provides oracle jvm with the ability to create and access objects in multiple sessions from a single client and services that handle multiple server objects in multiple sessions. this allows the jvm to distinguish objects based on the session in which they are activated. the standard corb... 下一页