1 Oracle Flashback Technologies COUG Presentation – Feb 2010 Feb 25, 2010 Ray Smith

2 What are my objectives today? Introduce you to some flashback technologies Raise your awareness of what’s available I won’t go over everything, 1 hour, not 5 days.. Maybe light a spark so you’ll go play too. Fly through the slides as quickly as possible. Go break my system and fix it… lots of times Agenda:

3 Flashback technologies Flashback Query Flashback Table Flashback Drop Flashback Versions Query Flashback Transaction Query Flashback Database Flashback Data Archive

4 Flashback technologies Flashback Query SQL> exec dbms_flashback package.. 9i R1. Scary code: DECLARE CURSOR emp_cur IS SELECT * FROM EMPLOYEE; v_rec emp_cur%rowtype; BEGIN DBMS_FLASHBACK.ENABLE_AT_TIME ('25-FEB-10 08:10:58'); open emp_cur; DBMS_FLASHBACK.DISABLE; LOOP fetch emp_cur into v_rec; EXIT WHEN emp_cur%NOTFOUND; INSERT INTO EMPLOYEE_TEMP VALUES (v_rec.emp_id, v_rec.name, v_rec.age ); END LOOP; close emp_cur; COMMIT; END; SQL> SELECT.. FROM.. AS OF…. WHERE

5 Flashback technologies Flashback Table SQL> flashback table … to timestamp … SQL> flashback table … to SCN … Flashback Drop Use of Recyclebin flashback table … to before drop;

6 Flashback technologies Flashback Versions Query Ability to capture changes to data over a given time. VERSIONS_STARTTIME (start timestamp of version); VERSIONS_STARTSCN (start SCN of version); VERSIONS_ENDTIME (end timestamp of version); VERSIONS_ENDSCN (end SCN of version); VERSIONS_XID (transaction ID of version); and VERSIONS_OPERATION (DML operation of version).

7 Flashback technologies Flashback Transaction Query Who run that? What was it? What is the UNDO code? Use of FLASHBACK_TRANSACTION_QUERY SQL> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA; SQL> select * from FLASHBACK_TRANSACTION_QUERY where xid= HEXTORAW(' A D');

8 Flashback technologies Flashback Database – through RESETLOGS (10.2) Create a flash recovery area Restart database ( mount exclusive ) SQL> ALTER DATASE FLASHBACK ON; SQL> ALTER SYSTEM SET db_flashback_retention_target = ; SQL> ALTER DATABASE OPEN; Restore Points create restore point PREQA_TESTING; create restore point PREQA_TESTING guarantee flashback database; drop restore point PREQA_TESTING;

9 Flashback technologies Flashback Data Archive SQL> create FLASHBACK ARCHIVE default tablespace quota 200M retention 1 MONTH; SQL> alter table flashback archive ;

10 Why are DBA’s avoiding using Flashback options? Complicated to setup – I think.. Too confusing.. I don’t have time to figure it out It slows down my system.. I think It’s new, so probably not so reliable

11 Why DBA’s should get to know it… It’s actually quite good. It can seriously save your bacon. Fast recoveries

12 How do you configure Flashback? It Depends.. Flashback Query – no setup required – Just undo Flashback Table – no setup required – Just undo Flashback Drop – Recyclebin – on by default. Flashback Versions - no setup required – Just undo Flashback Database – Requires a flash recovery area / feature to be switched on. Flashback Transaction – may require supplimental data Flashback Data Archives – needs flashback tablespace

13 How to Flashback Database? FLASHBACK DATABASE TO [BEFORE] SCN FLASHBACK DATABASE TO [BEFORE] TIMESTAMP FLASHBACK DATABASE TO [BEFORE] RESTORE POINT

14 Live Demo

15 Summary Start playing with flashback. Potential issues ERROR at line 1: ORA-08185: Flashback not supported for user SYS