Oracle DBMS_TRANSACTION Demos

Oracle DBMS_TRANSACTION Version 11.2.0.3

General Information

Purpose

Provides access to SQL transaction statements from stored procedures

AUTHID

CURRENT_USER

Dependencies

DBMS_AQADM_SYS	DBMS_ISCHED	MGMT_DELTA
DBMS_ASSERT	DBMS_LOGMNR_INTERNAL	MGMT_USER
DBMS_DEFER	DBMS_PRVTAQIM	PENDING_SESSIONS$
DBMS_DEFER_INTERNAL_SYS	DBMS_PRVTAQIP	PENDING_SUB_SESSIONS$
DBMS_DEFER_SYS	DBMS_SNAPSHOT	PENDING_TRANS$
DBMS_IJOB

Exceptions

Error Code	Reason
ORA-08175	DISCRETE_TRANSACTION_FAILED: Cannot be performed as a discrete transaction
ORA-08176	CONSISTENT_READ_FAILURE: Data changed by an operation that does not generate rollback data

First Available

7.3.4

Security Model

Owned by SYS: EXECUTE is granted to PUBLIC

Source

{ORACLE_HOME}/rdbms/admin/dbmstrns.sql

Subprograms

ADVISE_COMMIT	COMMIT_FORCE	ROLLBACK
ADVISE_NOTHING	LOCAL_TRANSACTION_ID	ROLLBACK_FORCE
ADVISE_ROLLBACK	PURGE_LOST_DB_ENTRY	ROLLBACK_SAVEPOINT
BEGIN_DISCRETE_TRANSACTION	PURGE_MIXED	SAVEPOINT
COMMIT	READ_ONLY	STEP_ID
COMMIT_COMMENT	READ_WRITE	USE_ROLLBACK_SEGMENT

ADVISE_COMMIT

Equivalent to SQL "ALTER SESSION ADVISE COMMIT"

dbms_transaction.advise_commit;

exec dbms_transaction.advise_commit;

ADVISE_NOTHING

Equivalent to SQL "ALTER SESSION ADVISE NOTHING"

dbms_transaction.advise_nothing;

exec dbms_transaction.advise_nothing;

ADVISE_ROLLBACK

Equivalent to SQL "ALTER SESSION ADVISE ROLLBACK"

dbms_transaction.advise_rollback;

exec dbms_transaction.advise_rollback;

BEGIN_DISCRETE_TRANSACTION

Set "discrete transaction mode" for this transaction

dbms_transaction.begin_discrete_transaction;

exec dbms_transaction.begin_discrete_transaction;

COMMIT

Equivalent to SQL "COMMIT"

dbms_transaction.commit;

exec dbms_transaction.commit;

COMMIT_COMMENT

Comment a commit statement

dbms_transaction.commit_comment(cmnt IN VARCHAR2);

CREATE TABLE t (
testcol NUMBER(2));

INSERT INTO t (testcol) VALUES (1);

exec dbms_transaction.commit_comment('Commiting a test record');

set linesize 121

SELECT local_tran_id, global_tran_id, state, mixed, advice,
tran_comment
FROM dba_2pc_pending;

COMMIT_FORCE

Equivalent to SQL "COMMIT FORCE

dbms_transaction.commit_force(
xid IN VARCHAR2, -- local or global transaction id
scn IN VARCHAR2 DEFAULT NULL); -- system change number

exec dbms_transaction.commit_force(xid, scn);

LOCAL_TRANSACTION_ID

Returns local (to instance) unique identifier for current transaction. Returns null if there is no current transaction.

dbms_transaction.local_transaction_id(
create_transaction BOOLEAN := FALSE) RETURN VARCHAR2;

conn uwclass/uwclass

SELECT dbms_transaction.local_transaction_id
FROM dual;

CREATE TABLE t (
testcol NUMBER(3));

INSERT INTO t
VALUES (1);

SELECT dbms_transaction.local_transaction_id
FROM dual;

CREATE OR REPLACE FUNCTION atf RETURN VARCHAR2 IS
PRAGMA AUTONOMOUS_TRANSACTION;
x VARCHAR2(20);
BEGIN
INSERT INTO t
(testcol)
VALUES
(2);

x := dbms_transaction.local_transaction_id;
COMMIT;

RETURN x;
END atf;
/

set serveroutput on

DECLARE
x VARCHAR2(20);
BEGIN
x := atf;
dbms_output.put_line(x);

INSERT INTO t VALUES (3);

x := dbms_transaction.local_transaction_id;
dbms_output.put_line(x);
COMMIT;
END;
/

PURGE_LOST_DB_ENTRY

Purge in-doubt transaction if remote database is destroyed

Follow linkto the TRANSACTION page of the library for more information on use of this proc.

When a failure occurs during commit processing, automatic recovery will consistently resolve the results at all sites involved in the transaction. However, if the remote database is destroyed or recreated before recovery completes, then the entries used to control recovery in DBA_2PC_PENDING and associated tables will never be removed, and recovery will periodically retry. Procedure purge_lost_db_entry allows removal of such transactions from the local site.

dbms_transaction.purge_lost_db_entry(xid IN VARCHAR2); -- tx id

exec dbms_transaction.purge_lost_db_entry(xid);

PURGE_MIXED

Purge in-doubt 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 will flag entries in DBA_2PC_PENDING by setting the MIXED column to a value of 'yes'. Oracle will never automatically delete information about a mixed outcome transaction. When the application or DBA is sure 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.

dbms_transaction.purge_mixed(xid IN VARCHAR2); -- transaction id

exec dbms_transaction.purge_mixed(xid);

READ_ONLY

Equivalent to SQL "SET TRANSACTION READ ONLY"

dbms_transaction.read_only;

exec dbms_transaction.read_only;

READ_WRITE

Equivalent to SQL "SET TRANSACTION READ WRITE"

dbms_transaction.read_write;

exec dbms_transaction.read_write;

ROLLBACK

Equivalent to SQL "ROLLBACK".

dbms_transaction.rollback;

exec dbms_transaction.rollback;

ROLLBACK_FORCE

Equivalent to SQL "ROLLBACK FORCE <text>"

dbms_transaction.rollback_force(xid IN VARCHAR2); -- tx id

exec dbms_transaction.rollback_force(xid);

ROLLBACK_SAVEPOINT

Equivalent to SQL "ROLLBACK TO SAVEPOINT <savepoint_name>"

dbms_transaction.rollback_savepoint(savept IN VARCHAR2);

exec dbms_transaction.rollback_savepoint('SP2');

SAVEPOINT

Equivalent to SQL "SAVEPOINT <savepoint_name>"

dbms_transaction.savepoint(savept IN VARCHAR2);

exec dbms_transaction.savepoint('SP2');

STEP_ID

Return local (to local transaction) unique positive integer that orders the DML operations of transaction

dbms_transaction.step_id RETURN NUMBER;

exec dbms_transaction.step_id
FROM dual;

USE_ROLLBACK_SEGMENT

Equivalent to SQL "SET TRANSACTION USE ROLLBACK SEGMENT

Deprecated

Used to select a specific named rollback segment for a transaction. As rollback segments will not be part of future Oracle releases, and should not exist in a well designed 9i database, this should not be used.

dbms_transaction.use_rollback_segment(rb_name IN VARCHAR2);

exec dbms_transaction.use_rollback_segment(rbs01);