Exporting the Server Parameter File
You can use the CREATE PFILE statement to export a server parameter file (SPFILE) to a text initialization parameter file. Doing so might be necessary for several reasons:

For diagnostic purposes, listing all of the parameter values currently used by an instance. This is analogous to the SQL*Plus SHOW PARAMETERS command or selecting from the V$PARAMETER or V$PARAMETER2 views.

To modify the &spfile;server parameter file by first exporting it, editing the resulting text file, and then re-creating it using the CREATE SPFILE statement

The exported file can also be used to start up an instance using the PFILE clause.

You must have the SYSDBA or the SYSOPER system privilege to execute the CREATE PFILE statement. The exported file is created on the database server system. It contains any comments associated with the parameter in the same line as the parameter setting.

The following example creates a text initialization parameter file from the SPFILE:

CREATE PFILE FROM SPFILE;

i went through the documentation and found out too.Basically we have to manually re-create the PFILE again after changing any parameters in SPFILE.

One of the problems with the SPFILE is that it is a binary file and it not readable. So you can't easily see its contents.

When I need to see what is set in the SPFILE, I issue the following:

CREATE PFILE='/home/oracle/pfile.txt' FROM SPFILE;

I'm not a DBA. Thank you for explaining it in such a simple manner, I enjoyed reading it.

So, the only drawback (from my point of view) of the whole SPFILE story is that the file is binary. Wouldn't it be simpler if it was a pure txt file, so that you could modify it in case "it has a bad parameter value"? It appears that you still need a PFILE, modify it, (according to best practices) create SPFILE from PFILE, discard PFILE. Hm?

Well, I'd say I see a complete klutz every year... and sometimes it's me... wrongly counting the number of 0 when modifying sga or target max size.