172 DBMS_TRANSACTION
The DBMS_TRANSACTION package provides access to SQL transaction statements from stored procedures.
See Also:
Oracle Database SQL Language Reference
172.1 DBMS_TRANSACTION Security Model
This package runs with the privileges of calling user, rather than the package owner SYS
.
172.2 Summary of DBMS_TRANSACTION Subprograms
This table lists the DBMS_TRANSACTION
subprograms and briefly describes them.
Table 172-1 DBMS_TRANSACTION Package Subprograms
Subprogram | Description |
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Returns the local (to instance) unique identifier for the current transaction |
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Enables removal of incomplete transactions from the local site when the remote database is destroyed or re-created before recovery completes |
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Deletes information about a given mixed outcome transaction |
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Equivalent to the SQL statement:
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equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Equivalent to the SQL statement:
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Returns local (to local transaction) unique positive integer that orders the DML operations of a transaction |
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Equivalent to the SQL statement:
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172.2.1 ADVISE_COMMIT Procedure
This procedure is equivalent to the SQL statement: ALTER SESSION ADVISE COMMIT
Syntax
DBMS_TRANSACTION.ADVISE_COMMIT;
172.2.2 ADVISE_NOTHING Procedure
This procedure is equivalent to the SQL statement: ALTER SESSION ADVISE NOTHING
Syntax
DBMS_TRANSACTION.ADVISE_NOTHING;
172.2.3 ADVISE_ROLLBACK Procedure
This procedure is equivalent to the SQL statement: ALTER SESSION ADVISE ROLLBACK
Syntax
DBMS_TRANSACTION.ADVISE_ROLLBACK;
172.2.4 COMMIT Procedure
This procedure is equivalent to the SQL statement: COMMIT
This procedure is included for completeness, the functionality being already implemented as part of PL/SQL.
Syntax
DBMS_TRANSACTION.COMMIT;
172.2.5 COMMIT_COMMENT Procedure
This procedure is equivalent to the SQL statement: COMMIT COMMENT <text>
Syntax
DBMS_TRANSACTION.COMMIT_COMMENT ( cmnt VARCHAR2);
Parameters
Table 172-2 COMMIT_COMMENT Procedure Parameters
Parameter | Description |
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|
Comment to associate with this commit. |
172.2.6 COMMIT_FORCE Procedure
This procedure is equivalent to the SQL statement: COMMIT FORCE <text>, <number>"
Syntax
DBMS_TRANSACTION.COMMIT_FORCE ( xid VARCHAR2, scn VARCHAR2 DEFAULT NULL);
Parameters
Table 172-3 COMMIT_FORCE Procedure Parameters
Parameter | Description |
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Local or global transaction ID. |
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System change number. |
172.2.7 LOCAL_TRANSACTION_ID Function
This function returns the local (to instance) unique identifier for the current transaction. It returns null if there is no current transaction.
Syntax
DBMS_TRANSACTION.LOCAL_TRANSACTION_ID ( create_transaction BOOLEAN := FALSE) RETURN VARCHAR2;
Parameters
Table 172-4 LOCAL_TRANSACTION_ID Function Parameters
Parameter | Description |
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If true, then start a transaction if one is not currently active. |
172.2.8 PURGE_LOST_DB_ENTRY Procedure
Procedure PURGE_LOST_DB_ENTRY
purges entries that control database recovery from a local site.
When a failure occurs during commit processing, automatic recovery consistently resolves the results at all sites involved in the transaction. However, if the remote database is destroyed or re-created before recovery completes, then the entries used to control recovery in DBA_2PC_PENDING
and associated tables are never removed, and recovery will periodically retry. Procedure PURGE_LOST_DB_ENTRY
enables removal of such transactions from the local site.
Syntax
DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY ( xid VARCHAR2);
Parameters
Table 172-5 PURGE_LOST_DB_ENTRY Procedure Parameters
Parameter | Description |
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Must be set to the value of the |
Usage Notes
WARNING:
PURGE_LOST_DB_ENTRY should only be used when the other database is lost or has been re-created. Any other use may leave the other database in an unrecoverable or inconsistent state.
Before automatic recovery runs, the transaction may show up in DBA_2PC_PENDING
as state "collecting", "committed", or "prepared". If the DBA has forced an in-doubt transaction to have a particular result by using "commit force" or "rollback force", then states "forced commit" or "forced rollback" may also appear. Automatic recovery normally deletes entries in any of these states. The only exception is when recovery finds a forced transaction which is in a state inconsistent with other sites in the transaction; in this case, the entry is left in the table and the MIXED
column has the value 'yes'.
However, under certain conditions, it may not be possible for automatic recovery to run. For example, a remote database may have been permanently lost. Even if it is re-created, it gets a new database ID, so that recovery cannot identify it (a possible symptom is ORA-02062
). In this case, the DBA may use the procedure PURGE_LOST_DB_ENTRY
to clean up the entries in any state other than "prepared". The DBA does not need to be in any particular hurry to resolve these entries, because they are not holding any database resources.
The following table indicates what the various states indicate about the transaction and what the DBA actions should be:
Table 172-6 PURGE_LOST_DB_ENTRY Procedure States
State of Column | State of Global Transaction | State of Local Transaction | Normal DBA Action | Alternative DBA Action |
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Note:
Use only if significant reconfiguration has occurred so that automatic recovery cannot resolve the transaction. Examples are total loss of the remote database, reconfiguration in software resulting in loss of two-phase commit capability, or loss of information from an external transaction coordinator such as a TP monitor.
Note:
Examine and take any manual action to remove inconsistencies; then use the procedure PURGE_MIXED
.
172.2.9 PURGE_MIXED Procedure
This procedure deletes information about a given mixed outcome transaction
When in-doubt transactions are forced to commit or rollback (instead of letting automatic recovery resolve their outcomes), there is a possibility that a transaction can have a mixed outcome; some sites commit, and others rollback. Such inconsistency cannot be resolved automatically by Oracle. However, Oracle flags entries in DBA_2PC_PENDING
by setting the MIXED
column to a value of 'yes'.
Oracle never automatically deletes information about a mixed outcome transaction. When the application or DBA is certain that all inconsistencies that might have arisen as a result of the mixed transaction have been resolved, this procedure can be used to delete the information about a given mixed outcome transaction.
Syntax
DBMS_TRANSACTION.PURGE_MIXED ( xid VARCHAR2);
Parameters
Table 172-7 PURGE_MIXED Procedure Parameters
Parameter | Description |
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|
Must be set to the value of the |
172.2.10 READ_ONLY Procedure
This procedure is equivalent to the SQL statement SET TRANSACTION READ ONLY
.
Syntax
DBMS_TRANSACTION.READ_ONLY;
172.2.11 READ_WRITE Procedure
This procedure is equivalent to the SQL statement:
SET TRANSACTION READ WRITE
Syntax
DBMS_TRANSACTION.READ_WRITE;
172.2.12 ROLLBACK Procedure
This procedure is equivalent to the SQL statement ROLLBACK
.
This procedure is included for completeness, the functionality being already implemented as part of PL/SQL.
Syntax
DBMS_TRANSACTION.ROLLBACK;
172.2.13 ROLLBACK_FORCE Procedure
This procedure is equivalent to the SQL statement ROLLBACK FORCE <text>
.
Syntax
DBMS_TRANSACTION.ROLLBACK_FORCE ( xid VARCHAR2);
Parameters
Table 172-8 ROLLBACK_FORCE Procedure Parameters
Parameter | Description |
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Local or global transaction ID. |
172.2.14 ROLLBACK_SAVEPOINT Procedure
This procedure is equivalent to the SQL statement ROLLBACK TO SAVEPOINT <savepoint_name>
.
This procedure is included for completeness, the functionality being already implemented as part of PL/SQL.
Syntax
DBMS_TRANSACTION.ROLLBACK_SAVEPOINT ( savept VARCHAR2);
Parameters
Table 172-9 ROLLBACK_SAVEPOINT Procedure Parameters
Parameter | Description |
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Savepoint identifier. |
172.2.15 SAVEPOINT Procedure
This procedure is equivalent to the SQL statement SAVEPOINT <savepoint_name>
.
This procedure is included for completeness, the feature being already implemented as part of PL/SQL.
Syntax
DBMS_TRANSACTION.SAVEPOINT ( savept VARCHAR2);
Parameters
Table 172-10 SAVEPOINT Procedure Parameters
Parameter | Description |
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Savepoint identifier. |
172.2.16 STEP_ID Function
This function returns local (to local transaction) unique positive integer that orders the DML operations of a transaction.
Syntax
DBMS_TRANSACTION.STEP_ID RETURN NUMBER;
172.2.17 USE_ROLLBACK_SEGMENT Procedure
This procedure is equivalent to the SQL statement SET TRANSACTION USE ROLLBACK SEGMENT <rb_seg_name>
.
Syntax
DBMS_TRANSACTION.USE_ROLLBACK_SEGMENT ( rb_name VARCHAR2);
Parameters
Table 172-11 USE_ROLLBACK_SEGMENT Procedure Parameters
Parameter | Description |
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Name of rollback segment to use. |