Database Reference
In-Depth Information
The fact that the ADR can grow quite large implies that some space man-
agement may be required from time to time. This would be something
you would consider as a part of the various maintenance processes to be
implemented on an active database system.
The Oracle ADR
The ADR is a standardized set of directories that are functionally defined within the ADR
framework. This means that each directory location has a specific purpose and stores specific
types of files. The root directory of the ADR is called the
ADR_BASE
. This location is defined
by the database parameter
DIAGNOSTIC_DEST
. The
DIAGNOSTIC_DEST
parameter is set in one
of the following ways:
■
By directly setting the
DIAGNOSTIC_DEST
parameter in the database parameter file.
This will cause the directories related to ADR to be created under the directory
defined in the
DIAGNOSTIC_DEST
directory. The name of the root directory will be
DIAGNOSTIC_DEST/diag
.
■■
By setting the Oracle OS environment variable
ORACLE_BASE
. In this case, the
DIAGNOSTIC_DEST
directory will be created under the
ORACLE_BASE
directory.
The name of the root directory will be
$ORACLE_BASE/diag
.
■
If
ORACLE_BASE
is not set, then
DIAGNOSTIC_DEST
will be located under
ORACLE_HOME
(i.e.,
$ORACLE_HOME/diag
).
The location where the
DIAGNOSTIC_DEST
is assigned is known as the
ADR BASE
directory.
All other ADR directories are created and written to under this
ADR BASE
directory.
Under
ADR BASE
, there is a series of directories that are predefined and are used to store
specific types of data. The standardized ADR directory structure is shown in Figure 6.1.
For example, let's say you have set the
DIAGNOSTIC_DEST
parameter in your database
to the location
/u01/app/oracle
. The ADR directory structure that Oracle would create
would begin at
/u01/app/oracle
, which would become the
ADR_BASE
.
Under the
ADR_BASE
, there will be several
ADR_HOME
directories. Each of these
ADR_HOME
directories is specific to a given component that writes into that structure. For example,
assume that you have created a database called
orcl
. Further, assume that this is an RAC
database and that there are two instances,
orcl1
and
orcl2
. In this case, there are essen-
tially two unique
ADR_HOME
directories that will be defined. Thus, you have two different
defined locations for your
orcl
RAC database, as shown in Table 6.2.
■
TABle 6.2
ADR Directory Locations
Name
Location
ADR_BASE
/u01/app/oracle
ADR_HOME
/u01/app/oracle/diag/rdbms/orcl/orcl1
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