Diagnosing the Database and Managing Performance - OCP: Oracle Database 12c Administrator Certified Professional - page 401

monitor reports, network tracing, and all other error diagnostic data. In Oracle 12 c , ADR is
the diagnostic data repository for Automatic Storage Management (ASM), the database, and
many other Oracle server products.
The ADR stores information in files outside the database so the information is available
whether or not the database is up. The files are stored in a directory structure that includes
a home directory for each instance of each product.
ADR Initialization Parameters
Since the Oracle 12 c ADR provides a single repository location for the alert log and all dump
files and trace files, there is no longer a need for the BACKGROUND_DUMP_DEST , CORE_DUMP_DEST ,
and USER_DUMP_DEST initialization parameters. They are deprecated and ignored. Now you
use the initialization parameter DIAGNOSTIC_DEST to designate the location of the ADR.
SQL> show parameter diag
NAME TYPE VALUE
------------------------------------ ----------- ---------
diagnostic_dest string C:\ORACLE
The default value for DIAGNOSTIC_DEST is $ORACLE_BASE . If the ORACLE_BASE environ-
ment variable is not set, then $ORACLE_HOME/log is used for DIAGNOSTIC_DEST . The value
of DIAGNOSTIC_DEST is referred to as the ADR base or ADR root .
Directory Structure of the Automatic Diagnostic Repository
Within the DIAGNOSTIC_DEST directory, Oracle builds the hierarchy of directories to support
the ADR. This is the basic pattern:
<diagnostic_dest>/diag/rdbms/<dbname>/<instname>
For the examples used in this chapter, the following represents the correct ADR home :
C:\oracle\diag\rdbms\orcl\orcl
These are some important directories that you need to know about:
Incident Each incident gets its own subdirectory within the incident directory.
Alert The alert log is written to the alert directory.
cdump Core dumps are written to this directory.
Trace Trace files are written to the trace directory.
See Figure 9.1 for an example directory structure, which shows other subdirectories of
the ADR home that store information such as incident packages, health monitor reports, the
DDL log, and the debug log.