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Oracle 12c进程结构 01

翻译 Oracle 作者:wanghanjun 时间:2015-12-24 09:31:29 0 删除 编辑
原文来自http://docs.oracle.com/database/121/CNCPT/process.htm#CNCPT008

Introduction to Processes进程介绍           

A process is a mechanism in an operating system that can run a series of steps. The process execution architecture depends on the operating system. For example, on Windows an Oracle background process is a thread of execution within a process. On Linux and UNIX, an Oracle process is either an operating system process or a thread within an operating system process.
一个进程是在操作系统中用于一些特定步骤实现特定功能的一个方法.进程的执行方法依赖于操作系统.比如说,在Windows的一个Oracle进程是一个进程中的的执行线程.Linux和Unix中, 一个Oracle的进程 也许是一个操作系统进程,或者是一个操作系统进程中的线程.

Processes run code modules. All connected Oracle Database users must run the following modules to access a database instance:
多数进程的运行时基于代码的编写方式, 所有连接到ORACLE数据库中的用户必须使用以下的方式来访问数据库实例.

  • Application or Oracle Database utility
    应用或者数据库工具                           

    A database user runs a database application, such as a precompiler program or a database tool such as SQL*Plus, that issues SQL statements to a database.
    一个数据库用户启动了一个数据库应用,比如预编辑器,或者一个sql plus的数据库工具,发出了一条SQL语句                                                                                       

  • Oracle database code
    Oracle数据库代码         

    Each user has Oracle database code executing on his or her behalf that interprets and processes the application's SQL statements.
    每一个用户会拥有一些数据库代码,这些代码经过解释和编译体现为应用的SQL语句

A process normally runs in its own private memory area. Most processes can periodically write to an associated trace file (see "Trace Files").
一般情况下一个进程运行在它自己的自由内存空间中。绝对大数进程会周期性的生成相关的Trace文件

如果有兴趣也可以参照如下内容                                
"Tools for Database Administrators" and "Tools for Database Developers

Types of Processes 进程类型

A database instance contains or interacts with the following types of processes:
一个数据库实例包含以下进程的类型                                                  

  • A client process runs the application or Oracle tool code.
    运行应用程序或者Oracle工具的客户端进程                                                                           

  • An Oracle process is a unit of execution that runs the Oracle database code. In the multithreaded architecture, an Oracle process can be an operating system process or a thread within an operating system process. Oracle processes include the following subtypes:
    一个Oracle的进程,是一个运行 Oracle数据库代码的可执行但愿. 在多线程结构中,一个Oracle进程可以是一个操作系统进程,或者是一个操作系统进程中的线程.Oracle进程包含以下类型

    • A background process starts with the database instance and perform maintenance tasks such as performing instance recovery, cleaning up processes, writing redo buffers to disk, and so on.
      后台进程.随着数据库实例的启动而运行,用于执行维护任务,例如执行实例级别的回复,清除没有用的进程,将redo buffer进入磁盘中等.                   

    • A server process performs work based on a client request.
      系统进程,执行是基于客户端请求的任务。             

      For example, these processes parse SQL queries, place them in the shared pool, create and execute a query plan for each query, and read buffers from the database buffer cache or from disk.
      比如说,有一些进程用于解析SQL查询,将这些SQL放入共享池中,创建并且依据执行计划来执行每一个查询,以及从数据库缓存或者磁盘中读取数据        

      Note:

      Server processes, and the process memory allocated in these processes, run in the database instance. The instance continues to function when server processes terminate.
      系统进程, 以及分配给这些进程的内容,都运行在数据库实例中,当服务器进程中断的时候实例会继续提供服务

    • A slave process performs additional tasks for a background or server process.
      从属进程,用于执行一些针对后台进程还有服务器进程的 额外的任务

      The process structure varies depending on the operating system and the choice of Oracle Database options. For example, you can configure the code for connected users for
      dedicated server or shared server connections. In a shared server architecture, each server process that runs database code can serve multiple client processes.
      进程结果的变化依赖与操作系统和数据库选项的调整。比如说,你可以通过代码配置将数据库条调整问专用服务器或者共享服务器。在一个共享服务器结构中,没一个运行有数据库代码的服务器进程都可以对多个客户端进程提供服务                                                                       


      Figure 15-1 shows a system global area (SGA) and background processes using dedicated server connections. For each user connection, a client process runs the application. This client process that is different from the dedicated server process that runs the database code. Each client process is associated with its own server process, which has its own program global area (PGA).
      下图列出了系统全局区的结构图,包含用于专用服务器连接的后台进程.每一个用户连接都针对一个客户端进程运行应用的程序客户端进程与专用服务器进程不同的是,每一个客户端进程都关联到它自己对应的服务器进程,并且每一个与它关联的服务器进程都有自己的程序全局区




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