What is Oracle database SPFILE ?
INTRODUCING the SPFILE
Oracle provides two different types of mutually exclusive
parameter files that you can use, PFILE and SPFILE. Let’s look at the SPFILE in a bit more detail.
SPFILE
SPFILE stands for Server Parameter
File. It is an extension of the initialization parameter storage mechanism,
which allows some additional advantages as compared to the simple text based
init.ora file. This feature aims at advancing towards Oracle's self-tuning
capabilities. As the name states, the file is present on the server side and is
not required on the client to start the instance.
An SPFILE uses the same formatting for its file name as
the PFILE, except the word spfile replaces init. For instance, if your
ORACLE_SID is testdb, the resulting spfile would be called spfiletestdb.ora.
- It is a binary file and the use of editors to modify it is not supported. The only way of changing parameter values is by using the ALTER SYSTEM SET/RESET command.
- If using the PFILE option, parameter changes done with the ALTER SYSTEM command need to be manually changed in the init.ora file to reflect the changes on future startups. With SPFILE, the ALTER SYSTEM command can update the binary file as well. This allows the changes to be persistent across startups.
- Since it is binary, it is prone to becoming corrupt if things go wrong. As a backup strategy, create copies of the SPFILE and convert it to a text-based PFILE for safe keeping.
- The PFILE is required from the client from where the instance is being started. The SPFILE is not required to be from the client from where the instance is started. This comes in handy when we are trying to start the database remotely.
- In a multi-instance Real Application cluster system, a single copy of the SPFILE can be used for all instances. The SPFILE maintains different format styles to support both the common values for all instances as well as specific values for individual instances.
- You only need to be connected as SYSDBA/SYSOPER to create the SPFILE or PFILE. The database need not be started. This option is useful in case the SPFILE has been corrupted and you need to rebuild it from a PFILE.
Parameter
files are by default situated in
·
$ORACLE_HOME/dbs on
UNIX platform or
·
%ORACLE_HOME%\database on Windows platform.
Tags: Oracle, Spfile, Startup
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