I have a database called NEWSDB running in a unix environment.
Under my $ORACLE_HOME/dbs, I have about 10 different init.ora files saved under different names. I am wondering which exact one is my database is using or if it's using all of them. Is it using all of them? The impression that I am having is that, any time a changed is made to the init.ora files, it's numbered in order to identify how many times changes where made to the init.ora file. I am trying to find out if the database uses all of init.ora files or not.
each database instance uses one and only one parameter file when starting up.
Depending upon in what mode you want to run the database (DSS, OLTP or a mix) you can create many different copies of this parameter file and make necessary changes in there.
Then you can start the instance by a command like following --
(or choose whatever init file you want to start te instance with)
Sambavan is right in that in most cases the init file looks like initSIDName.ora but it could be any name as long as your OS supports that naming convetion. In Windows you can use a init file like "init.newsdb.ora003" without any problem
As they had made changes to the original one, they would have saved the previous working copy, to revert back incase the new one fails to start the instance. So in your case, it looks like the one with initSID.ora is the actual current one. Check the dates of creation of the old ones and you would be able to find out the order in which they had been incarnated.
you need to modify the fine that you plan to use to startup the database (the changes will take effect only when you shutdown and startup the database)
The only way to know what file was used to startup the database the last time is the method Sambavan mentioned...get the parameter values and compare with each one of the init files (chances are high that it would be initnewsdb.ora )
But you have to understand this that if you (or someone else) plan to startup the database in future using some other init file, you will need to make the changes there as well.