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Oracle® Database PL/SQL Packages and Types Reference
10g Release 2 (10.2)

Part Number B14258-01
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104 DBMS_STORAGE_MAP

With the DBMS_STORAGE_MAP package, you can communicate with the Oracle background process FMON to invoke mapping operations that populate mapping views. FMON communicates with operating and storage system vendor-supplied mapping libraries.

This chapter contains the following topics:


Using DBMS_STORAGE_MAP


Overview

The following terminology and descriptions will help you understand the DBMS_STORAGE_MAP API:


Operational Notes

For MAP_ELEMENT, MAP_FILE, and MAP_ALL: Invoking these functions when mapping information already exists will refresh the mapping if configuration IDs are supported. If configuration IDs are not supported, then invoking these functions again will rebuild the mapping.

See Also:

Oracle Database Administrator's Guide for a discussion of the configuration ID, an attribute of the element or file that is changed.

Summary of DBMS_STORAGE_MAP Subprograms

Table 104-1 DBMS_STORAGE_MAP Package Subprograms

Subprogram Description
DROP_ALL Function
Drops all mapping information in the shared memory of the instance
DROP_ELEMENT Function
Drops the mapping information for the element defined by elemname
DROP_FILE Function
Drops the file mapping information defined by filename
LOCK_MAP Procedure
Locks the mapping information in the shared memory of the instance
MAP_ALL Function
Builds the entire mapping information for all types of Oracle files (except archive logs), including all directed acyclic graph (DAG) elements
MAP_ELEMENT Function
Builds mapping information for the element identified by elemname
MAP_FILE Function
Builds mapping information for the file identified by filename
MAP_OBJECT Function
Builds the mapping information for the Oracle object identified by the object name, owner, and type
RESTORE Function
Loads the entire mapping information from the data dictionary into the shared memory of the instance
SAVE Function
Saves information needed to regenerate the entire mapping into the data dictionary
UNLOCK_MAP Procedure
Unlocks the mapping information in the shared memory of the instance.


DROP_ALL Function

This function drops all mapping information in the shared memory of the instance.

Syntax

DBMS_STORAGE_MAP.DROP_ALL(
      dictionary_update IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-2 DROP_ALL Function Parameters

Parameter Description
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.


DROP_ELEMENT Function

This function drops the mapping information for the element defined by elemname.

Syntax

DBMS_STORAGE_MAP.DROP_ELEMENT(
   elemname          IN VARCHAR2,
   cascade           IN BOOLEAN,
   dictionary_update IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-3 DROP_ELEMENT Function Parameters

Parameter Description
elemname The element for which mapping information is dropped.
cascade If TRUE, then DROP_ELEMENT is invoked recursively on all elements of the DAG defined by elemname, if possible.
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.


DROP_FILE Function

This function drops the file mapping information defined by filename.

Syntax

DBMS_STORAGE_MAP.DROP_FILE(
   filename          IN VARCHAR2,
   cascade           IN BOOLEAN,
   dictionary_update IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-4 DROP_FILE Function Parameters

Parameter Description
filename The file for which file mapping information is dropped.
cascade If TRUE, then the mapping DAGs for the elements where the file resides are also dropped, if possible.
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.


LOCK_MAP Procedure

This procedure locks the mapping information in the shared memory of the instance. This is useful when you need a consistent snapshot of the V$MAP tables. Without locking the mapping information, V$MAP_ELEMENT and V$MAP_SUBELEMENT, for example, may be inconsistent.

Syntax

DBMS_STORAGE_MAP.LOCK_MAP;

MAP_ALL Function

This function builds the entire mapping information for all types of Oracle files (except archive logs), including all directed acyclic graph (DAG) elements. It obtains the latest mapping information because it explicitly synchronizes all mapping libraries.

Syntax

DBMS_STORAGE_MAP.MAP_ALL(
   max_num_fileext   IN NUMBER DEFAULT 100,
   dictionary_update IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-5 MAP_ALL Function Parameters

Parameter Description
max_num_fileext Defines the maximum number of file extents to be mapped. This limits the amount of memory used when mapping file extents. The default value is 100; max_num_fileextent is an overloaded argument.
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.

Usage Notes

You must explicitly call MAP_ALL in a cold startup scenario.


MAP_ELEMENT Function

This function builds mapping information for the element identified by elemname. It may not obtain the latest mapping information if the element being mapped, or any one of the elements within its I/O stack (if cascade is TRUE), is owned by a library that must be explicitly synchronized.

Syntax

DBMS_STORAGE_MAP.MAP_ELEMENT(
   elemname          IN VARCHAR2,
   cascade           IN BOOLEAN,
   dictionary_update IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-6 MAP_ELEMENT Function Parameters

Parameter Description
elemname The element for which mapping information is built.
cascade If TRUE, all elements within the elemname I/O stack DAG are mapped.
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.


MAP_FILE Function

This function builds mapping information for the file identified by filename. Use this function if the mapping of one particular file has changed. The Oracle database server does not have to rebuild the entire mapping.

Syntax

DBMS_STORAGE_MAP.MAP_FILE(
   filename           IN VARCHAR2, 
   filetype           IN VARCHAR2,
   cascade            IN BOOLEAN,
   max_num_fileextent IN NUMBER DEFAULT 100,
   dictionary_update  IN BOOLEAN DEFAULT TRUE);

Parameters

Table 104-7 MAP_FILE Function Parameters

Parameter Description
filename The file for which mapping information is built.
filetype Defines the type of the file to be mapped. It can be "DATAFILE", "SPFILE", "TEMPFILE", "CONTROLFILE", "LOGFILE", or "ARCHIVEFILE".
cascade Should be TRUE only if a storage reconfiguration occurred. For all other instances, such as file resizing (either through an ALTER SYSTEM command or DML operations on extended files), cascade can be set to FALSE because the mapping changes are limited to the file extents only.

If TRUE, mapping DAGs are also built for the elements where the file resides.

max_num_fileextent Defines the maximum number of file extents to be mapped. This limits the amount of memory used when mapping file extents. The default value is 100; max_num_fileextent is an overloaded argument.
dictionary_update If TRUE, mapping information in the data dictionary is updated to reflect the changes. The default value is TRUE; dictionary_update is an overloaded argument.

Usage Notes

This function may not obtain the latest mapping information if the file being mapped, or any one of the elements within its I/O stack (if cascade is TRUE), is owned by a library that must be explicitly synchronized.


MAP_OBJECT Function

This function builds the mapping information for the Oracle object identified by the object name, owner, and type.

Syntax

DBMS_STORAGE_MAP.MAP_OBJECT(
   objname  IN  VARCHAR2,
   owner    IN  VARCHAR2,
   objtype  IN  VARCHAR2);

Parameters

Table 104-8 MAP_OBJECT Function Parameters

Parameter Description
objname The name of the object.
owner The owner of the object.
objtype The type of the object.


RESTORE Function

This function loads the entire mapping information from the data dictionary into the shared memory of the instance. You can invoke RESTORE only after a SAVE operation. You must explicitly call RESTORE in a warm startup scenario.

Syntax

DBMS_STORAGE_MAP.RESTORE;

SAVE Function

This function saves information needed to regenerate the entire mapping into the data dictionary.

Syntax

DBMS_STORAGE_MAP.SAVE;

UNLOCK_MAP Procedure

This procedure unlocks the mapping information in the shared memory of the instance.

Syntax

DBMS_STORAGE_MAP.UNLOCK_MAP;