Tuning and Monitoring RMAN and the Automatic Diagnostic Workflow - OCP: Oracle Database 12c Administrator Certified Professional - page 268

FiGURe 6.1 The Oracle ADR directory structure

ADR
base

diag

rdbms

DB_UNIQUE_NAME

ADR
base

SID

alert cdump incident trace (others)

In this case, the ADR_BASE is the directory structure /u01/app/oracle . Note that Oracle
created all the directories including the ADR_BASE directory itself and all of the directories
under that directory.
Under the ADR_BASE directory is the main directory of the ADR, which is called diag .
Under the diag directory you will see a number of directories that have been created. Each
of these directories represents an Oracle component. For example, the rdbms directory rep-
resents the Oracle database component.
Under the rdbms directory will be additional directories that represent the database and
instance that the underlying data belongs to.
Then, under the instance directory, there are a number of directories that represent dif-
ferent types of files that the database will create at various times and places. For example,
the database alert log, trace files, and various diagnostic data are stored in the various
directories. As an example, the following directory is used to store trace files for the orcl1
instance of the orcl database:
C:\APP\ORACLE\diag\rdbms\orcl12c\orcl12c\trace
As you can see in the code example that is printed below. Also in that code output you
can see the various ADR locations by using the V$DIAG_INFO view, as shown in the follow-
ing example. Note that this example demonstrates the ADR locations for a single-instance
Oracle database; therefore it has only one ADR_HOME :

SELECT * FROM V$DIAG_INFO;