About Initialization Parameters

About Initialization Parameters
Managing an Oracle instance includes configuring parameters that affect the basic
operation of the Oracle instance. These parameters are called initialization parameters.
The Oracle instance reads initialization parameters from a file at startup.
During installation, when you select a preconfigured database workload available in
DBCA, the initialization parameters are optimized for typical use in the environment
that you specified. As the number of database users increases and the workload
increases, you might have to alter some initialization parameters. You can make these
changes using the Initialization Parameter page in EM Express, or by using an advisor
provided by Oracle Database, such as the Memory Advisor. See "Optimizing Memory
Usage with the Memory Advisors" on page 10-31 for more information.
After being read from a file, initialization parameters are retained in memory, where
the values for many of them can be changed dynamically. There are two types of
parameter files. The type of file used to start the instance determines if dynamic
initialization parameter changes persist across database shutdown and startup. The
parameter file types are:
■ Server parameter file
The server parameter file, commonly known as the SPFILE, is the preferred form
of initialization parameter file, and is a binary file that can be written to and read
by the database. It must not be edited manually. It is stored on the host computer
on which Oracle Database is running. Changes are made when you use EM
Express or SQL*Plus to modify one or more initialization parameters, or when
Oracle Database itself makes changes for self-tuning purposes. Any changes to it
persist across database shutdown and startup operations.
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