Oracle Flashback Transaction Query with Oracle Flashback Version Query

Oracle Flashback Transaction Query with Oracle Flashback Version Query

In this example, a database administrator does this:

DROP TABLE emp;
CREATE TABLE emp (
  empno   NUMBER PRIMARY KEY,
  empname VARCHAR2(16),
  salary  NUMBER
);
INSERT INTO emp (empno, empname, salary) VALUES (111, 'Mike', 555);
COMMIT;

DROP TABLE dept;
CREATE TABLE dept (
  deptno   NUMBER,
  deptname VARCHAR2(32)
);
INSERT INTO dept (deptno, deptname) VALUES (10, 'Accounting');
COMMIT;

Now emp and dept have one row each. In terms of row versions, each table has one version of one row. Suppose that an erroneous transaction deletes empno 111 from table emp:

UPDATE emp SET salary = salary + 100 WHERE empno = 111;
INSERT INTO dept (deptno, deptname) VALUES (20, 'Finance');
DELETE FROM emp WHERE empno = 111;
COMMIT;

Next, a transaction reinserts empno 111 into the emp table with a new employee name:

INSERT INTO emp (empno, empname, salary) VALUES (111, 'Tom', 777);
UPDATE emp SET salary = salary + 100 WHERE empno = 111;
UPDATE emp SET salary = salary + 50 WHERE empno = 111;
COMMIT;

The database administrator detects the application error and must diagnose the problem. The database administrator issues this query to retrieve versions of the rows in the emp table that correspond to empno 111. The query uses Oracle Flashback Version Query pseudocolumns:

SELECT versions_xid XID, versions_startscn START_SCN,
  versions_endscn END_SCN, versions_operation OPERATION,
  empname, salary
FROM emp
VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE
WHERE empno = 111;

Results are similar to:

XID               START_SCN    END_SCN O EMPNAME              SALARY
---------------- ---------- ---------- - ---------------- ----------
09001100B2200000   10093466            I Tom                     927
030002002B210000   10093459            D Mike                    555
0800120096200000   10093375   10093459 I Mike                    555

3 rows selected.

The results table rows are in descending chronological order. The third row corresponds to the version of the row in the table emp that was inserted in the table when the table was created. The second row corresponds to the row in emp that the erroneous transaction deleted. The first row corresponds to the version of the row in emp that was reinserted with a new employee name.

The database administrator identifies transaction 030002002B210000 as the erroneous transaction and uses Oracle Flashback Transaction Query to audit all changes made by this transaction:

SELECT  xid, start_scn, commit_scn, operation, logon_user, undo_sql
FROM flashback_transaction_query
WHERE xid = HEXTORAW('000200030000002D');

Results are similar to:

XID               START_SCN COMMIT_SCN OPERATION LOGON_USER
---------------- ---------- ---------- --------- ------------------------------
UNDO_SQL
--------------------------------------------------------------------------------

030002002B210000   10093452   10093459 DELETE    HR
insert into "HR"."EMP"("EMPNO","EMPNAME","SALARY") values ('111','Mike','655');

030002002B210000   10093452   10093459 INSERT    HR
delete from "HR"."DEPT" where ROWID = 'AAATjuAAEAAAAJrAAB';

030002002B210000   10093452   10093459 UPDATE    HR
update "HR"."EMP" set "SALARY" = '555' where ROWID = 'AAATjsAAEAAAAJ7AAA';

030002002B210000   10093452   10093459 BEGIN     HR

4 rows selected.

To make the result of the next query easier to read, the database administrator uses these SQL*Plus commands:

COLUMN operation FORMAT A9
COLUMN table_name FORMAT A10
COLUMN table_owner FORMAT A11

To see the details of the erroneous transaction and all subsequent transactions, the database administrator performs this query:

SELECT xid, start_scn, commit_scn, operation, table_name, table_owner
FROM flashback_transaction_query
WHERE table_owner = 'HR'
AND start_timestamp >=
  TO_TIMESTAMP ('2002-04-16 11:00:00','YYYY-MM-DD HH:MI:SS');

Results are similar to:

XID               START_SCN COMMIT_SCN OPERATION TABLE_NAME TABLE_OWNER
---------------- ---------- ---------- --------- ---------- -----------
02000E0074200000   10093435   10093446 INSERT    DEPT       HR
030002002B210000   10093452   10093459 DELETE    EMP        HR
030002002B210000   10093452   10093459 INSERT    DEPT       HR
030002002B210000   10093452   10093459 UPDATE    EMP        HR
0800120096200000   10093374   10093375 INSERT    EMP        HR
09001100B2200000   10093462   10093466 UPDATE    EMP        HR
09001100B2200000   10093462   10093466 UPDATE    EMP        HR
09001100B2200000   10093462   10093466 INSERT    EMP        HR

8 rows selected.