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From Here to Eternity: UsingOracle’s Flashback Data Archive
to Protect Critical Data
Gary Garrison
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“People Are
Our GreatestAsset.”
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While a nice quote thisstatement is wrong. Data is an
organization’s greatest asset,and liability.
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Agenda
• Need for Flashback Data Archive (FDA)or Total Recall
• Architecture
• Best Practices
• Examples
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Architecture
• Uses undo tablespace• New background process (FBDA)
• Small impact on performance• System tables that hold data
modifications are partitioned
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Best Practices
• Do not archive every table• Backup the archive tablespace
• Use dedicated tablespaces forFlashback Data Archive
• Index the system tables that hold datamodifications
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Examples (as of)select
old_emp.employee_id,old_emp.last_name,old_emp.first_name,
old_emp.salary,new_salary
from hr.employeesas of timestamp to_timestamp('2007-12-30 07:00:00','yyyy-mm-ddhh24:mi:ss') old_emp
join (select employee_id,salary as new_salary
from hr.employees) new_emp
on old_emp.employee_id = new_emp.employee_id
where old_emp.salary != new_emp.new_salary
EMPLOYEE_ID LAST_NAME FIRST_NAME SALARYNEW_SALARY
----------- ---------- ---------- ---------- ----------206 Gietz William 12000 100
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Example (versions between)11gR2
select
versions_starttime,versions_endtime,versions_operation,versions_xid,employee_id,salary
from hr.employees versions between timestamp
to_timestamp('2007-12-30 10:00:00','yyyy-mm-dd hh24:mi:ss')
and systimestamp
where employee_id = 206
VERSIONS_STARTTIME VERSIONS_ENDTIME E SALARY
------------------------- ------------------------- - ----------30-DEC-07 10.41.32 AM U 12000
30-DEC-07 10.14.34 AM 30-DEC-07 10.41.32 AM U 50000
30-DEC-07 10.14.34 AM 100000
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References
• How to Turn Back Time: Using Oracle’sFlashback Technology to Fix Logical Errors.Gary Garrison.
• Oracle Database Advanced ApplicationDeveloper's Guide 11g Release 2 (11.2).Using Flashback Data Archive (Oracle Total
Recall).
• Oracle Total Recall with Oracle Database 11g
Release 2.
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Conclusion
FDA is a criticalcomponent a
good dataprotection
strategy
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Questions
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