Re: newbie question - init.ora vs. alter database

Greg wrote:

> Hi,
>
> I was performing an ALTER DATABASE ARCHIVELOG on my Oracle DB and I
> was wondering if its necessary for me to include the following
> parameters in the init.ora file as well:
>
> log_archive_start = true
> log_archive_dest_1 = "location=/opt/oracle/arch"
> log_archive_format = arch_%t_%S.log
>
> From what I understand, the ALTER statement needs to be performed in
> any case, but I'm not sure whether these init.ora configurations are
> mandatory as well (or if there is just a way to perform these steps
> while the database is open).
>
> Sorry, but I'm a little confused on the relationship between the DB,
> the init file and the control files. If anyone has a decent link to
> explain the relationship between these things, this might help me out.
>
> Thx.

(My) recommended reading - great for a quick & light weight jump start - is Oracle Essentials from O'Reilly http://oracle.oreilly.com

You also really need to get into the concepts manual (http://docs.oracle.com - register at http://otn.oracle.com first - it's free and it's worth your time.)

The reason for pointing to the docco is you need to understand the difference between Database and Instance. I mean, really understand! The concepts manual also goes into a fair bit of explanation in answer to your specific question. Further explanation is given in the Database Administrator's Guide.

Now, init is short for 'initialize' or 'initial state' and you can safely assume the init.ora describes the state we want, or the way the database should be, when initially opening.

After it is open, you can change the state for a number of reasons. This is an alteration from the initial state, and can be accomplished using the alter command. All the database alter variants are described in the SQL Language manual (under Alter database ... ) along with reasons and sample usage.

The control files contain the current 'control' state of the entire database, including the snapshot of the the way it was opened and alterred, as well as the locations and critical information about all the data files, log files, etc. This information is used heavily during the startup and especially during an automatic recovery. Consider the control files to be a micro-database describing the real database to Oracle.

HTH Received on Fri May 16 2003 - 12:11:26 CDT