Oracle parameter file Introduction

Oracle parameter file Introduction

After the Oracle database is started, you can use the select * from v $ parameter statement to view all the parameters used by the Oracle database.

Oracle parameter files are divided into spfile binary files and pfile text files. Currently, the database generally uses the spfile binary file as the parameter file for Oracle startup. Differences between spfile and pfile:

1. spfile is a binary file (which can be viewed using string spfileorcl. ora). It cannot be modified using a text editor, but can only be dynamically modified using commands in sqlplus. If pfile is a text file, you can directly use the text editor to modify it. It takes effect after the database is restarted.

2. spfile must be stored on the server, generally under the $ Oracle_HOME/dbs directory. For pfile, it can be stored on the client, and the database can be started through the pfile on the client.

3. spfile and pfile can be dynamically converted to SQL commands (whether or not the database instance is started or not)

Use pfile to create spfile create pfile = '/u01/app/Oracle/dbs/spfileorcl. ora 'from pfile = '/u01/app/Oracle/dbs/initorcl. ora '(or use create spfile from pfile)

4. If the start database does not specify the parameter file (if the sid is orcl), search for the parameter file spfileorcl. ora> initorcl. ora in the $ Oracle_HOME/dbs directory.

5. You can specify a parameter file to start the database (only the pfile file can be used, not the spfile file)

Startup pfile = '/u01/app/Oracle/dbs/init. ora' (use the pfile file)

6. For parameters not specified in the parameter file, the default values of relevant parameters are used.

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