Initialization Parameter Files and Server Parameter Files (287)

To start an instance, Oracle must read either an initialization parameter file or a
server parameter file. These files contain a list of configuration parameters for that
instance and database. Oracle traditionally stored initialization parameters in a text
initialization parameter file. You can also choose to maintain initialization parameters
in a binary server parameter file (SPFILE).

Initialization parameters stored in a server parameter file are persistent, in that any
changes made to the parameters while an instance is running can persist across
instance shutdown and startup.

Initialization parameters are divided into two groups: basic and advanced. In the
majority of cases, it is necessary to set and tune only the basic parameters to get
reasonable performance. In rare situations, modification to the advanced parameters
may be needed for optimal performance.

Most initialization parameters belong to one of the following groups:
■ Parameters that name things, such as files
■ Parameters that set limits, such as maximums
■ Parameters that affect capacity, such as the size of the SGA, which are called
variable parameters
Among other things, the initialization parameters tell Oracle:
■ The name of the database for which to start up an instance
■ How much memory to use for memory structures in the SGA
■ What to do with filled redo log files
■ The names and locations of the database control files
■ The names of undo tablespaces in the database

初始化引數檔案與伺服器引數檔案
1. 引數可以分為以下幾種型別:
* 用於命名的引數，例如為檔案命名
* 用於設限的引數，例如設定一個最大值
* 用於設定容量的引數，例如設定 SGA 的大小

[@more@]