The DBMS_LOGSTDBY
package provides subprograms for configuring and managing the logical standby database environment.
See Also:
Oracle Data Guard Concepts and Administration for more information about SQL Apply and logical standby databasesThis chapter contains the following topics:
Overview
Operational Notes
Deprecated Subprograms
This section contains topics which relate to using the DBMS_LOGSTDBY
package.
The DBMS_LOGSTDBY
package helps you manage the SQL Apply (logical standby database) environment. The subprograms in the DBMS_LOGSTDBY
package help you to accomplish the following main objectives:
Manage configuration parameters used by SQL Apply.
For example, controlling how transactions are applied on the logical standby database, how much shared pool is used, and how many processes are used by SQL Apply to mine and apply the changes.
Ensure an appropriate level of supplemental logging is enabled, and a LogMiner dictionary is built correctly for logical standby database creation.
Provide a way to skip the application of changes to selected tables or entire schemas in the logical standby database, and specify ways to handle exceptions encountered by SQL Apply.
Allow controlled access to tables in the logical standby database that may require maintenance.
Ensure you use the correct case when supplying schema and table names to the DBMS_LOGSTDBY
package. For example, the following statements show incorrect and correct syntax for a SKIP
procedure that skips changes to OE.TEST
.
Incorrect statement:
EXECUTE DBMS_LOGSTDBY.SKIP (stmt => 'DML', schema_name => 'oe', - object_name => 'test', proc_name => null);
Because the names are specified with lowercase characters, the transactions that update these columns will still be applied to the logical standby database.
Correct statement:
EXECUTE DBMS_LOGSTDBY.SKIP (stmt => 'DML', schema_name => 'OE', - object_name => 'TEST', proc_name => null);
A prototype role, LOGSTDBY_ADMINISTRATOR
, is created by default with RESOURCE
, and EXECUTE
on DBMS_LOGSTDBY
privileges. If you choose to use this role, consider granting ALTER DATABASE
and ALTER SESSION
privileges to the role so that the grantee can start and stop SQL Apply and can enable and disable the database guard. Oracle recommends using an account with DBA privileges to perform administration tasks on logical standby databases.
The six procedures associated with skipping transactions (SKIP
and UNSKIP
, SKIP_ERROR
and UNSKIP_ERROR
, and SKIP_TRANSACTION
and UNSKIP_TRANSACTION
) all require DBA
privileges to execute because their scope may contain wildcard schemas. Oracle recommends that where SKIP
procedures are specified, these be owned by a secure account with appropriate privileges on the schemas they act on (for example, SYS
).
The transaction_consistency
parameter of the APPLY_SET Procedure is being deprecated with this release of the Oracle Database. The transaction_consistency
parameter is being replaced by the preserve_commit_order
parameter.
Table 56-1 DBMS_LOGSTDBY Package Subprograms
Subprogram | Description |
---|---|
Sets the values of various parameters that configure and maintain SQL Apply |
|
Restores the default values of various parameters that configure and maintain SQL Apply |
|
Ensures supplemental logging is enabled properly and builds the LogMiner dictionary |
|
Creates and populates a table in the standby database from a corresponding table in the primary database |
|
Used after a failover, this procedure ensures a local logical standby database that was not involved in the failover has not processed more redo than the new primary database and reports the set of archive redo log files that must be replaced to ensure consistency |
|
Identifies the archived redo log files that have been applied to the logical standby database and are no longer needed by SQL Apply |
|
Records relevant metadata (including the LogMiner Multiversioned Data Dictionary) in the redo stream in case a database that has recently changed its role to a primary database following a failover operation fails to do so during the failover process |
|
Moves metadata tables required by SQL Apply to the user-specified tablespace. By default, the metadata tables are created in the |
|
Specifies rules that control database operations that should not be applied to the logical standby database |
|
Specifies rules regarding what action to take upon encountering errors |
|
Specifies transactions that should not be applied on the logical standby database. Be careful in using this procedure, because not applying specific transactions may cause data corruption at the logical standby database. |
|
Deletes rules specified by the |
|
Deletes rules specified by the |
|
Deletes rules specified by the |
Use this procedure to set values of parameters that configure and manage SQL Apply in a logical standby database environment. SQL Apply cannot be running when you use this procedure.
DBMS_LOGSTDBY.APPLY_SET ( parameter IN VARCHAR, value IN VARCHAR);
Table 56-2 APPLY_SET Procedure Parameters
Parameter | Description |
---|---|
|
Automatically deletes archived redo log files once they have been applied on the logical standby database. Set to |
|
Number of megabytes from shared pool in System Global Area (SGA) that SQL Apply will use. The default value is 30 megabytes or one quarter of the value set for |
|
Number of parallel query servers that SQL Apply uses to read and apply redo. It defaults to the value of the |
|
Number of recent events that will be visible through the |
|
Regardless of the level chosen, modifications done to the same row are always applied in the same order as they happened in the primary database. See the Usage Notes for details and recommendations. |
|
Controls whether skipped errors (as described by the
|
|
Controls whether skipped DDL statements are recorded in the
|
|
Controls whether DDL statements that have been applied to the logical standby database are recorded in the
|
|
Controls the number of |
|
Controls the number of |
Table 56-3 APPLY_SET Procedure Exceptions
Exception | Description |
---|---|
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
|
Logical Standby metadata operation in progress |
SQL Apply must be stopped before calling the APPLY_SET
procedure.
Use the APPLY_UNSET
procedure to restore the default settings of a parameter.
See Oracle Data Guard Concepts and Administration for help with tuning SQL Apply and for information about setting appropriate values for different parameters.
To record DDLs in the DBA_LOGSTDBY_EVENTS
view and in the alert log, issue the following statement:
SQL> EXECUTE DBMS_LOGSTDBY.APPLY_SET('RECORD_APPLIED_DDL', TRUE);
Use the APPLY_UNSET
procedure to restore the default values of the parameters that you changed with the APPLY_SET
procedure.
DBMS_LOGSTDBY.APPLY_UNSET ( parameter IN VARCHAR);
The parameter information for the APPLY_UNSET
procedure is the same as that described for the APPLY_SET
procedure. See Table 56-2 for complete parameter information.
Table 56-4 APPLY_UNSET Procedure Exceptions
Exception | Description |
---|---|
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
|
Logical Standby metadata operation in progress |
SQL Apply must be stopped before calling the APPLY_UNSET
procedure.
Use the APPLY_SET
procedure to specify a nondefault value for a parameter.
If you previously specified that applied DDLs show up in the DBA_LOGSTDBY_EVENTS
view and the alert log, you can restore the default behavior of SQL Apply regarding applied DDL statements with the following statement:
SQL> EXECUTE DBMS_LOGSTDBY.APPLY_UNSET('RECORD_APPLIED_DDL');
Use this procedure on the primary database to record relevant metadata (LogMiner dictionary) information in the redo log, which will subsequently be used by SQL Apply. This procedure will enable database-wide primary- and unique-key supplemental logging, if necessary.
DBMS_LOGSTDBY.BUILD;
Supplemental log information includes extra information in the redo logs that uniquely identifies a modified row in the logical standby database, and also includes information that helps efficient application of changes to the logical standby database.
LogMiner dictionary information allows SQL Apply to interpret data in the redo logs.
DBMS_LOGSTDBY.BUILD
should be run only once for each logical standby database you want to create. You do not need to use DBMS_LOGSTDBY.BUILD for each RAC instance.
To build the LogMiner dictionary in the redo stream of the primary database and to record additional information so that a logical standby database can be instantiated, issue the following SQL statement at the primary database
SQL> EXECUTE DBMS_LOGSTDBY.BUILD;
This procedure creates and populates a table in the standby database from a corresponding table in the primary database. The table requires the name of the database link (dblink)
as an input parameter. If the table already exists in the logical standby database, it will be dropped and re-created based on the table definition at the primary database. This procedure only brings over the data associated with the table, and not the associated indexes and constraints.
Use the INSTANTIATE_TABLE
procedure to:
Add a table to a standby database.
Re-create a table in a standby database.
DBMS_LOGSTDBY.INSTANTIATE_TABLE ( schema_name IN VARCHAR2, table_name IN VARCHAR2, dblink IN VARCHAR2);
Table 56-5 INSTANTIATE_TABLE Procedure Parameters
Parameter | Description |
---|---|
|
Name of the schema |
|
Name of the table to be created or re-created in the standby database |
|
Name of the database link account that has privileges to read and lock the table in the primary database |
Table 56-6 INSTANTIATE_TABLE Procedure Exceptions
Exception | Description |
---|---|
|
Logical Standby apply must be stopped to allow this operation |
|
Logical Standby metadata operation in progress |
Use this procedure to create and populate a table in a way that keeps the data on the standby database transactionally consistent with the primary database.
This table will not be synchronized with the rest of the tables being maintained by SQL Apply and SQL Apply will not start to maintain it until the redo log that was current on the primary database at the time of execution is applied to the standby database.
SQL> EXECUTE DBMS_LOGSTDBY.INSTANTIATE_TABLE (- SCHEMA_NAME => 'HR', TABLE_NAME => 'EMPLOYEES', - DBLINK => 'INSTANTIATE_TBL_LINK');
The PREPARE_FOR_NEW_PRIMARY
procedure must be invoked at a logical standby database following a failover if that standby database was not the target of the failover operation. Such a standby database must process the exact same set of redo logs processed at the new primary database. This routine ensures that the local logical standby database has not processed more redo than the new primary database and reports the set of archive logs that must be replaced to ensure consistency. The set of replacement logs will be reported in the alert.log. These logs must be copied to the logical standby and registered using the ALTER DATABASE REGISTER LOGICAL LOGFILE
statement.
DBMS_LOGSTDBY.PREPARE_FOR_NEW_PRIMARY ( FORMER_STANDBY_TYPE IN VARCHAR2, DBLINK IN VARCHAR2);
Table 56-7 PREPARE_FOR_NEW_PRIMARY Procedure Parameters
Parameter | Description |
---|---|
|
The type of standby database that was the target of the failover operation to become the new primary database. Valid values are ' |
|
The name of a database link to the new primary database |
Table 56-8 PREPARE_FOR_NEW_PRIMARY Procedure Exceptions
Exception | Description |
---|---|
|
Invalid Logical Standby option. |
|
Failed to apply log data from previous primary. |
This routine is intended only for logical standby systems.This routine will fail if the new primary database was formerly a logical standby database and the LogMiner dictionary build has not completed successfully.Log files displayed in the alert log will be referred to as terminal logs. Users should keep in mind that file paths are relative to the new primary database and may not resolve locally.Upon manual registration of the terminal logs, users should complete the process by calling either START LOGICAL STANDBY APPLY
if the new primary database was formerly a physical standby database or START LOGICAL STANDBY APPLY NEW PRIMARY
if the new primary database was formerly a logical standby database.See the alert log for more details regarding the reasons for any exception.
SQL> EXECUTE DBMS_LOGSTDBY.PREPARE_FOR_NEW_PRIMARY ( - FORMER_STANDBY_TYPE => 'LOGICAL', - DBLINK => 'dblink_to_newprimary');
Identifies all archived redo log files that have been applied to the logical standby database and are no longer needed by SQL Apply. Once identified, you can issue operating system commands to delete some or all of the unnecessary archived redo log files.
DBMS_LOGSTDBY.PURGE_SESSION;
This procedure does not delete the archived redo log files. You must issue operating system commands to delete unneeded files.
This procedure updates the DBA_LOGMNR_PURGED_LOG
view that displays the archived redo log files that have been applied to the logical standby database.
In Oracle Database 10g Release 2, metadata related to the archived redo log files (and the actual archived redo log files) are purged automatically based on the default setting of the LOG_AUTO_DELETE
parameter described in the DBMS_LOGSTDBY.APPLY_SET
procedure described.
To identify and remove unnecessary files:
Enter the following statement on the logical standby database:
SQL> EXECUTE DBMS_LOGSTDBY.PURGE_SESSION;
Query the DBA_LOGMNR_PURGED_LOG
view to list the archived redo log files that can be removed:
SQL> SELECT * FROM DBA_LOGMNR_PURGED_LOG; FILE_NAME ------------------------------------ /boston/arc_dest/arc_1_40_509538672.log /boston/arc_dest/arc_1_41_509538672.log /boston/arc_dest/arc_1_42_509538672.log /boston/arc_dest/arc_1_43_509538672.log /boston/arc_dest/arc_1_44_509538672.log /boston/arc_dest/arc_1_45_509538672.log /boston/arc_dest/arc_1_46_509538672.log /boston/arc_dest/arc_1_47_509538672.log
Use operating system-specific commands to delete archived redo log files from the file system.
This procedure is used if a database that has recently changed its role to a primary database following a failover operation fails to record relevant metadata (including the LogMiner Multiversioned Data Dictionary) in the redo stream required for other logical standby databases.
DBMS_LOGSTDBY.REBUILD;
LogMiner Multiversioned Data Dictionary information is logged in the redo log files.The standby redo log files (if present) are archived.
SQL> EXECUTE DBMS_LOGSTDBY.REBUILD;
Moves metadata tables required by SQL Apply to the user-specified tablespace. By default, the metadata tables are created in the SYSAUX
tablespace.
DBMS_LOGSTDBY.SET_TABLESPACE( NEW_TABLESPACE IN VARCHAR2)
Table 56-10 SET_TABLE SPACE Procedure Parameters
Parameter | Description |
---|---|
|
Name of the new tablespace where metadata tables will reside. |
Table 56-11 SET_TABLESPACE Procedure Exceptions
Exception | Description |
---|---|
|
Logical Standby apply must be stopped to allow this operation |
|
Logical Standby metadata operation in progress |
To move metadata tables to a new tablespace named LOGSTDBY_TBS
, issue the following statement:
SQL> EXECUTE DBMS_LOGSTDBY.SET_TABLESPACE (new_tablespace => 'LOGSTDBY_TBS');
The SKIP
procedure can be used to define rules that will be used by SQL Apply to skip the application of certain changes to the logical standby database. For example, the SKIP
procedure can be used to skip changes to a subset of tables in the logical standby database. It can also be used to specify DDL statements that should not be applied at the logical standby database or should be modified before they are applied in the logical standby database. One reason why a DDL statement may need to be modified is to accommodate a different directory structure on the logical standby database.
DBMS_LOGSTDBY.SKIP ( stmt IN VARCHAR2, schema_name IN VARCHAR2 DEFAULT NULL, object_name IN VARCHAR2 DEFAULT NULL, proc_name IN VARCHAR2 DEFAULT NULL, use_like IN BOOLEAN DEFAULT TRUE, esc IN CHAR1 DEFAULT NULL);
Table 56-12 SKIP Procedure Parameters
Parameter | Description |
---|---|
|
Either a keyword that identifies a set of SQL statements or a specific SQL statement. The use of keywords simplifies configuration since keywords, generally defined by the database object, identify all SQL statements that operate on the specified object. Table 56-13 shows a list of keywords and the equivalent SQL statements, either of which is a valid value for this parameter. |
|
The name of one or more schemas (wildcards are permitted) associated with the SQL statements identified by the |
|
The name of one or more objects (wildcards are permitted) associated with the SQL statements identified by the |
|
Name of a stored procedure to call when SQL Apply determines that a particular statement matches the filter defined by the
This procedure returns a value that directs SQL Apply to perform one of the following: execute the statement, skip the statement, or execute a replacement statement. SQL Apply calls the stored procedure with the following call signature:
|
|
Allows pattern matching to isolate the tables that you want to skip on the logical standby database. The |
|
Identifies an escape character (such as the character "/") that you can use for pattern matching. If the escape character appears in the pattern before the character "%" or "_" then Oracle interprets this character literally in the pattern, rather than as a special pattern matching character. SeeOracle Database SQL Reference for more information about pattern matching. |
This procedure requires DBA
privileges to execute.
You cannot associate a stored procedure to be invoked in the context of a DML statement. For example, the following statement returns the ORA-16104: invalid Logical Standby option requested
error:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP(- stmt => 'DML', - schema_name => 'HR', - object_name => 'EMPLOYEES', - proc_name => 'DML_HANDLER');
Also, if an event matches multiple rules either because of the use of wildcards while specifying the rule or because of a specification of overlapping rules. For example, if you specify a rule for the SCHEMA_DDL
event for the HR.EMPLOYEES
table, and a rule for the ALTER TABLE
event for the HR.EMPLOYEES
table, only one of the matching procedures will be invoked (alphabetically, by procedure). In the following code example, consider the following rules:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP( - stmt => 'SCHEMA DDL', - schema_name => 'HR', - object_name => 'EMPLOYEES', - proc_name => 'SCHEMA_DDL_HANDLER'); SQL> EXECUTE DBMS_LOGSTDBY.SKIP( - stmt => 'ALTER TABLE', - schema_name => 'HR', - object_name => 'EMPLOYEES', - proc_name => 'TABLE_ALTER_HANDLER');
On encountering an ALTER TABLE
statement, the schema_ddl_handler
procedure will be invoked because its name will be at the top of an alphabetically sorted list of procedures that are relevant to the statement.Collisions on a rule set because of a specification containing wildcard entries are resolved in a similar fashion. For example, the rules in the following example will result in the empddl_handler
procedure being invoked upon encountering the ALTER TABLE HR.EMPLOYEES ADD COLUMN RATING NUMBER
statement:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP(- stmt => 'ALTER TABLE', - schema_name => 'HR', - object_name => 'EMP%', - proc_name => 'EMPDDL_HANDLER'); SQL> EXECUTE DBMS_LOGSTDBY.SKIP( - stmt => 'ALTER TABLE', - schema_name => 'HR', - object_name => 'EMPLOYEES', - proc_name => 'EMPLOYEE_DDL_HANDLER');
Use the SKIP
procedure with caution, particularly when skipping DDL statements. If a CREATE
TABLE
statement is skipped, for example, you must also specify other DDL statements that refer to that table in the SKIP
procedure. Otherwise, the statements will fail and cause an exception. When this happens, SQL Apply stops running.
Before calling the SKIP
procedure, SQL Apply must be halted. Do this by issuing an ALTER DATABASE STOP LOGICAL STANDBY APPLY
statement. Once all desired filters have been specified, issue an ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE
statement to start SQL Apply using the new filter settings.
See the UNSKIP
procedure for information about reversing (undoing) the settings of the SKIP
procedure.
For USER
statements, the SCHEMA_NAME
parameter will be the user and specify '%' for the OBJECT_NAME
parameter.
If the PROC_NAME
parameter is supplied, it must already exist in DBA_PROCEDURES
and it must execute with DEFINER
rights. If the procedure is declared with INVOKER
rights, the ORA-1031: insufficient privileges
message will be returned.
If the procedure returns a REPLACEMENT
statement, the REPLACEMENT
statement will be executed using the SYSTEM
and OBJECT
privileges of the owner of the procedure.
The PL/SQL block of a SKIP
procedure cannot contain transaction control statements (for example, COMMIT
, ROLLBACK
, SAVEPOINT
, and SET CONSTRAINT
) unless the block is declared to be an autonomous transaction.
Table 56-13 lists the supported values for the stmt
parameter of the SKIP
procedure. The left column of the table lists the keywords that may be used to identify the set of SQL statements to the right of the keyword. Any of the SQL statements in the right column, however, are also valid values. Note that keywords are generally defined by database object.
Table 56-13 Supported Values for the stmt
Parameter
Keyword | Associated SQL Statements |
---|---|
|
All DDL that does not pertain to a particular schema Note: |
|
All DDL statements that create, modify, or drop schema objects (for example: tables, indexes, and columns) Note: |
|
Includes DML statements on a table (for example: |
|
AUDIT CLUSTER CREATE CLUSTER DROP CLUSTER TRUNCATE CLUSTER |
|
CREATE CONTEXT DROP CONTEXT |
|
CREATE DATABASE LINK CREATE PUBLIC DATABASE LINK DROP DATABASE LINK DROP PUBLIC DATABASE LINK |
|
ALTER DIMENSION CREATE DIMENSION DROP DIMENSION |
|
CREATE DIRECTORY DROP DIRECTORY |
|
ALTER INDEX CREATE INDEX DROP INDEX |
|
ALTER FUNCTION ALTER PACKAGE ALTER PACKAGE BODY ALTER PROCEDURE CREATE FUNCTION CREATE LIBRARY CREATE PACKAGE CREATE PACKAGE BODY CREATE PROCEDURE DROP FUNCTION DROP LIBRARY DROP PACKAGE DROP PACKAGE BODY DROP PROCEDURE |
|
ALTER PROFILE CREATE PROFILE DROP PROFILE |
|
ALTER ROLE CREATE ROLE DROP ROLE SET ROLE |
|
ALTER ROLLBACK SEGMENT CREATE ROLLBACK SEGMENT DROP ROLLBACK SEGMENT |
|
ALTER SEQUENCE CREATE SEQUENCE DROP SEQUENCE |
|
CREATE PUBLIC SYNONYM CREATE SYNONYM DROP PUBLIC SYNONYM DROP SYNONYM |
|
ALTER TABLE CREATE TABLE DROP TABLE |
|
CREATE TABLESPACE DROP TABLESPACE TRUNCATE TABLESPACE |
|
ALTER TRIGGER CREATE TRIGGER DISABLE ALL TRIGGERS DISABLE TRIGGER DROP TRIGGER ENABLE ALL TRIGGERS ENABLE TRIGGER |
|
ALTER TYPE ALTER TYPE BODY CREATE TYPE CREATE TYPE BODY DROP TYPE DROP TYPE BODY |
|
ALTER USER CREATE USER DROP USER |
|
CREATE VIEW DROP VIEW |
Footnote 1 Java schema objects (sources, classes, and resources) are considered the same as procedure for purposes of skipping (ignoring) SQL statements.
Table 56-14 DBMS_LOGSTDBY.SKIP Procedure Exceptions
Exception | Description |
---|---|
|
Insufficient privileges:
|
|
Logical standby apply must be stopped to allow this operation. |
|
Invalid logical standby option requested. |
|
"Unable to interpret Indicates that a |
|
Logical standby metadata operation in progress. |
Example 1 Skipping all DML and DDL changes made to a schema
The following example shows how to specify rules so that SQL Apply will skip both DDL and DML statements made to the HR schema.
SQL> EXECUTE DBMS_LOGSTDBY.SKIP(STMT => 'SCHEMA DDL', - schema_name => 'HR', - table_name => '%', - proc_name => null); SQL> EXECUTE DBMS_LOGSTDBY.SKIP(STMT => 'DML', - schema_name => 'HR', - table_name => '%', - proc_name => null);
Example 2 Creating a procedure to handle different file system organization
For example, if the file system organization in the logical standby database is different than that in the primary database, you can write a SKIP
procedure to handle DDL statements with file specifications transparently.The following procedure can handle DDL statements as long as you follow a specific naming convention for the file specification string.
Create the SKIP
procedure to handle tablespace DDL statements:
CREATE OR REPLACE PROCEDURE sys.handle_tbs_ddl ( old_stmt IN VARCHAR2, stmt_typ IN VARCHAR2, schema IN VARCHAR2, name IN VARCHAR2, xidusn IN NUMBER, xidslt IN NUMBER, xidsqn IN NUMBER, action OUT NUMBER, new_stmt OUT VARCHAR2 ) AS BEGIN -- All primary file specification that contains a directory -- /usr/orcl/primary/dbs -- should go to /usr/orcl/stdby directory specification new_stmt = replace(old_stmt, '/usr/orcl/primary/dbs', '/usr/orcl/stdby'); action := DBMS_LOGSTDBY.SKIP_ACTION_REPLACE; EXCEPTION WHEN OTHERS THEN action := DBMS_LOGSTDBY.SKIP_ACTION_ERROR; new_stmt := NULL; END handle_tbs_ddl;
Register the SKIP
procedure with SQL Apply:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP (stmt => 'TABLESPACE', - proc_name => 'SYS.HANDLE_TBS_DDL');
Upon encountering an error, the logical standby database uses the criteria contained in this procedure to determine if the error should cause SQL Apply to stop. All errors to be skipped are stored in system tables that describe how exceptions should be handled.
DBMS_LOGSTDBY.SKIP_ERROR ( stmt IN VARCHAR2, schema_name IN VARCHAR2, object_name IN VARCHAR2, proc_name IN VARCHAR2, use_like IN BOOLEAN, esc IN CHAR1);
Table 56-15 SKIP_ERROR Procedure Parameters
Parameter | Description |
---|---|
|
Either a keyword that identifies a set of SQL statements or a specific SQL statement. The use of keywords simplifies configuration because keywords, generally defined by the database object, identify all SQL statements that operate on the specified object. Table 56-13 shows a list of keywords and the equivalent SQL statements, either of which is a valid value for this parameter. |
|
The name of one or more schemas (wildcards are permitted) associated with the SQL statements identified by the |
|
The name of one or more objects (wildcards are permitted) associated with the SQL statements identified by the |
|
Name of a stored procedure to call when SQL Apply determines a particular statement matches the filter defined by the
This procedure returns a value that directs SQL Apply to perform one of the following: execute the statement, skip the statement, or execute a replacement statement. SQL Apply calls the stored procedure with the following call signature:
|
|
Allows pattern matching to isolate the tables that you want to skip on the logical standby database. The |
|
Identifies an escape character (such as the characters "%" or "_") that you can use for pattern matching. If the escape character appears in the pattern before the character "%" or "_" then Oracle interprets this character literally in the pattern, rather than as a special pattern matching character. SeeOracle Database SQL Reference for more information about pattern matching. |
A stored procedure provided to the SKIP_ERROR
procedure is called when SQL Apply encounters an error that could shut down the application of redo logs to the standby database.
Running this stored procedure affects the error being written in the STATUS
column of the DBA_LOGSTDBY_EVENTS
table. The STATUS_CODE
column remains unchanged. If the stored procedure is to have no effect, that is, apply will be stopped, then the NEW_ERROR
is written to the events table. To truly have no effect, set NEW_ERROR
to ERROR
in the procedure.
If the stored procedure requires that a shutdown be avoided, then you must set NEW_ERROR
to NULL
.
This procedure requires DBA
privileges to execute.
For USER
statements, the SCHEMA_NAME
parameter will be the user and you should specify '%' for the OBJECT_NAME
parameter.
If the PROC_NAME
parameter is specified, it must already exist in DBA_PROCEDURES
and it must execute with DEFINERS
rights. If the procedure is declared with INVOKERS
rights, the ORA-1031: insufficient privileges
message will be returned.
The PL/SQL block of a SKIP_ERROR
procedure cannot contain transaction control statements (for example: COMMIT
, ROLLBACK
, SAVEPOINT
, and SET CONSTRAINT
) unless the block is declared to be an autonomous transaction using the following syntax:
PRAGMA AUTONOMOUS_TRANSACTION
Table 56-16 SKIP_ERROR Procedure Exceptions
Exception | Description |
---|---|
|
Insufficient privileges:
|
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
|
Logical Standby metadata operation in progress |
To skip errors on GRANT
statements on SYS
or HR
schemas, define a procedure handle_error_ddl
and register it. In the following example, assume that handle_error_ddl
is a free-standing procedure in the SYS
schema.
Create the error-handler procedure:
CREATE OR REPLACE PROCEDURE sys.handle_error_ddl ( old_stmt IN VARCHAR2, stmt_type IN VARCHAR2, schema IN VARCHAR2, name IN VARCHAR2, xidusn IN NUMBER, xidslt IN NUMBER, xidsqn IN NUMBER, error IN VARCHAR2, new_stmt OUT VARCHAR2 ) AS BEGIN -- Default to what we already have new_stmt := old_stmt; -- Ignore any GRANT errors on SYS or HR schemas IF INSTR(UPPER(old_stmt),'GRANT') > 0 THEN IF schema IS NULL OR (schema IS NOT NULL AND (UPPER(schema) = 'SYS' OR UPPER(schema) = 'HR' ) THEN new_stmt := NULL; -- record the fact that we just skipped an error on 'SYS' or 'HR' schemas -- code not shown here END IF; END IF; END handle_error_ddl; /
Register the error handler with SQL Apply:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP_ERROR ( - statement => 'NON_SCHEMA_DDL', - schema_name => NULL, - object_name => NULL, - proc_name => 'SYS.HANDLE_ERROR_DDL');
This procedure provides a way to skip (ignore) applying transactions to the logical standby database. You can skip specific transactions by specifying transaction identification information.
DBMS_LOGSTDBY.SKIP_TRANSACTION ( XIDUSN IN NUMBER, XIDSLT NUMBER IN NUMBER, XIDSQN NUMBER IN NUMBER);
Table 56-17 SKIP_TRANSACTION Procedure Parameters
Parameter | Description |
---|---|
|
Transaction ID undo segment number of the transaction being skipped |
|
Transaction ID slot number of the transaction being skipped |
|
Transaction ID sequence number of the transaction being skipped |
If SQL Apply stops due to a particular transaction (for example, a DDL transaction), you can specify that transaction ID and then continue to apply. You can call this procedure multiple times for as many transactions as you want SQL Apply to ignore.
CAUTION:
SKIP_TRANSACTION
is an inherently dangerous operation. Do not invoke this procedure unless you have examined the transaction in question through the V$LOGMNR_CONTENTS
view and have taken compensating actions at the logical standby database. SKIP_TRANSACTION
is not the appropriate procedure to invoke to skip DML changes to a table.
To skip a DML failure, use a SKIP
procedure, such as SKIP('DML','MySchema','MyFailed Table').
Using the SKIP_TRANSACTION
procedure for DML transactions may skip changes for other tables, thus logically corrupting them.
This procedure requires DBA
privileges to execute.
Use the DBA_LOGSTDBY_SKIP_TRANSACTION
view to list the transactions that are going to be skipped by SQL Apply.
Also, see the ALTER DATABASE START LOGICAL STANDBY SKIP FAILED TRANSACTION
statement in Oracle Database SQL Reference.
Table 56-18 SKIP_TRANSACTION Procedure Exceptions
Exception | Description |
---|---|
|
Need |
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
To skip a DDL transaction with (XIDUSN
, XIDSLT
, XIDSQN
) of (1.13.1726) you can register a rule as shown in the following example:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP_TRANSACTION (- XIDUSN => 1, XIDSLT => 13, XIDSQN => 1726);
Use the UNSKIP
procedure to delete rules specified earlier with the SKIP
procedure. The parameters specified in the UNSKIP
procedure must match exactly for it to delete an already-specified rule.
DBMS_LOGSTDBY.UNSKIP ( stmt IN VARCHAR2, schema_name IN VARCHAR2, object_name IN VARCHAR2);
The parameter information for the UNSKIP
procedure is the same as that described for the SKIP
procedure. See Table 56-12 for complete parameter information.
Table 56-19 UNSKIP Procedure Exceptions
Exception | Description |
---|---|
|
Need |
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
CAUTION:
If DML changes for a table have been skipped and not compensated for, you must follow the call to the UNSKIP
procedure with a call to the INSTANTIATE_TABLE
procedure to synchronize this table with those maintained by SQL Apply.
This procedure requires DBA privileges to execute.
Wildcards passed in the schema_name
or the object_name
parameter are not expanded. The wildcard character is matched at the character level. Thus, you can delete only one specified rule by invoking the UNSKIP
procedure, and you will need a distinct UNSKIP
procedure call to delete each rule that was previously specified.
For example, assume you have specified the following two rules to skip applying DML statements to the HR.EMPLOYEE
and HR.EMPTEMP
tables:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMPLOYEE', - PROC_NAME => null); SQL> EXECUTE DBMS_LOGSTDBY.SKIP (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMPTEMP', - PROC_NAME => null);
In the following example, the wildcard in the TABLE_NAME
parameter cannot be used to delete the rules that were specified:
SQL> EXECUTE DBMS_LOGSTDBY.UNSKIP (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMP%');
In fact, this UNSKIP
procedure matches neither of the rules, because the wildcard character in the TABLE_NAME
parameter is not expanded. Instead, the wildcard character will be used in an exact match to find the corresponding SKIP
rule.
Use the UNSKIP_ERROR
procedure to delete rules specified earlier with the SKIP_ERROR
procedure. The parameters specified in the UNSKIP_ERROR
procedure must match exactly for the procedure to delete an already-specified rule.
DBMS_LOGSTDBY.UNSKIP_ERROR ( stmt IN VARCHAR2, schema_name IN VARCHAR2, object_name IN VARCHAR2);
The parameter information for the UNSKIP_ERROR
procedure is the same as that described for the SKIP_ERROR
procedure. See Table 56-15 for complete parameter information.
Table 56-20 UNSKIP_ERROR Procedure Exceptions
Exception | Description |
---|---|
|
Need |
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
This procedure requires DBA
privileges to execute.
Wildcards passed in the schema_name
or the object_name
parameters are not expanded. Instead, the wildcard character is treated as any other character and an exact match is made. Thus, you can delete only one specified rule by invoking the UNSKIP_ERROR
procedure, and you need a distinct UNSKIP_ERROR
procedure call to delete each rule that you previously specified.
For example, assume you have specified the following two rules to handle the HR.EMPLOYEE
and HR.EMPTEMP
tables:
SQL> EXECUTE DBMS_LOGSTDBY.SKIP_ERROR (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMPLOYEE', - PROC_NAME => 'hr_employee_handler'); SQL> EXECUTE DBMS_LOGSTDBY.SKIP_ERROR (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMPTEMP', - PROC_NAME => 'hr_tempemp_handler');
In this case, the following UNSKIP
procedure cannot be used to delete the rules that you have specified:
SQL> EXECUTE DBMS_LOGSTDBY.UNSKIP_ERROR (STMT => 'DML',- SCHEMA_NAME => 'HR', - OBJECT_NAME => 'EMP%');
In fact, the UNSKIP
procedure will match neither of the rules, because the wildcard character in the OBJECT_NAME
parameter will not be expanded.
To remove a handler that was previously registered with SQL Apply from getting called on encountering an error, you can issue the following statement:
DBMS_LOGSTDBY.UNSKIP_ERROR ( - statement => 'NON_SCHEMA_DDL', - schema_name => NULL, - object_name => NULL);
Use the UNSKIP_TRANSACTION
procedure to delete rules specified earlier with the SKIP_TRANSACTION
procedure. The parameters specified in the UNSKIP_TRANSACTION
procedure must match exactly for the procedure to delete an already-specified rule.
DBMS_LOGSTDBY.UNSKIP_TRANSACTION ( XIDUSN NUMBER, XIDSLT NUMBER, XIDSQN NUMBER);
Table 56-21 UNSKIP_TRANSACTION Procedure Parameters
Parameter | Description |
---|---|
|
Transaction ID undo segment number of the transaction being skipped |
|
Transaction ID slot number of the transaction being skipped |
|
Transaction ID sequence number of the transaction being skipped |
Table 56-22 UNSKIP_TRANSACTION Procedure Exceptions
Exception | Description |
---|---|
|
Need |
|
Logical Standby apply must be stopped to allow this operation |
|
invalid Logical Standby option requested |
This procedure requires DBA
privileges to execute.
Query the DBA_LOGSTDBY_SKIP_TRANSACTION
view to list the transactions that are going to be skipped by SQL Apply.
To remove a rule that was originally specified to skip the application of a transaction with (XIDUSN
, XIDSLT
, XIDSQN
) of (1.13.1726) issue the following statement:
SQL> DBMS_LOGSTDBY.UNSKIP_TRANSACTION (XIDUSN => 1, XIDSLT => 13, XIDSQN => 1726);