When diagnosing a problem, you may want to work with diagnostic data from multiple database instances or components, or you may want to focus on diagnostic data from one instance or component. To work with diagnostic data from multiple instances or components, you must ensure that the ADR homes for all of these instances or components are current. To work with diagnostic data from only one instance or component, you must ensure that only the ADR home for that instance or component is current. You control the ADR homes that are current by setting the ADRCI homepath.
If multiple homes are current, this means that the homepath points to a directory in the ADR directory structure that contains multiple ADR home directories underneath it. To focus on a single ADR home, you must set the homepath to point lower in the directory hierarchy, to a single ADR home directory.
For example, if the Oracle RAC database with database name orclbi has two instances, where the instances have SIDs orclbi1 and orclbi2, and Oracle RAC is using a shared Oracle home, the following two ADR homes exist:
/diag/rdbms/orclbi/orclbi1/ /diag/rdbms/orclbi/orclbi2/
In all ADRCI commands and output, ADR home directory paths (ADR homes) are always expressed relative to ADR base. So if ADR base is currently /u01/app/oracle, the absolute paths of these two ADR homes are the following:
/u01/app/oracle/diag/rdbms/orclbi/orclbi1/ /u01/app/oracle/diag/rdbms/orclbi/orclbi2/
You use the SET HOMEPATH command to set one or more ADR homes to be current. If ADR base is /u01/app/oracle and you want to set the homepath to /u01/app/oracle/diag/rdbms/orclbi/orclbi2/, you use this command:
adrci> set homepath diag/rdbms/orclbi/orclbi2
When ADRCI starts, the homepath is null by default, which means that all ADR homes under ADR base are current. In the previously cited example, therefore, the ADR homes for both Oracle RAC instances would be current.
adrci> show homes ADR Homes: diag/rdbms/orclbi/orclbi1 diag/rdbms/orclbi/orclbi2
In this case, any ADRCI command that you run, assuming that the command supports more than one current ADR home, works with diagnostic data from both ADR homes. If you were to set the homepath to /diag/rdbms/orclbi/orclbi2, only the ADR home for the instance with SID orclbi2 would be current.
adrci> set homepath diag/rdbms/orclbi/orclbi2 adrci> show homes ADR Homes: diag/rdbms/orclbi/orclbi2
In this case, any ADRCI command that you run would work with diagnostic data from this single ADR home only.
Oracle Database Administrator's Guide for more information about the structure of ADR homes
"ADR Base"
"ADR Home"
"Homepath"