multiple instances on same machine

[bobinb]

I've read it's possible to have multiple instances on the same machine. On unix, would the .profile or bash_profile need to be set? If so can the instances just be seperated by commas in the ORACLE_SID parameter (ie: ORACLE_SID=instance1,instance2 export ORACLE_SID). Thanks

[stecal]

Setting ORACLE_SID to name1,name2,etc is not how the environment variable works.

You have a login shell. It has a set of environment variables, ORACLE_SID being one of them. IF that SID happens to be on the workstation you are on, the only real benefit you get is to do sqlplus username/password (no "@db_name" is needed). Having the SID set is useful when using DBCA, as it will read the SID and save you from typing in up to eight characters (max length of a SID name). Having the ORACLE_SID set is useful if you use an alias. Your "sp" alias could be "sqlplus username/password@$ORACLE_SID."

To connect to multiple SIDs, do that thru SQL*Plus (conn username/password@db_name2, etc.).