ORACLE 11G 新特性之_Flashback.ppt

19 Copyright ? 2009, Oracle. All rights reserved. Flashback Technology, LogMiner, and Data Pump Enhancements Copyright ? 2009, Oracle. All rights reserved. 19 - 2 Objectives pleting this lesson, you should be able to: ? Use Flashback Data Archive to create, protect, and use history data – Prepare your database – Create, change, and drop a flashback data archive – View flashback data archive metadata ? Use Flashback Transaction Backout – Set up Flashback Transaction prerequisites – Query transactions with and without dependencies – Choose backout options and flash back transactions ? Use Enterprise Manager LogMiner ? Use Data Pump legacy mode Copyright ? 2009, Oracle. All rights reserved. 19 - 3 Flashback Data Archive: Overview Transparently tracks historical changes to all Oracle data in a highly secure and efficient manner: ?“ Secure ”– No possibility to modify historical data – Retained according to your specifications – Automatically purged based on your retention policy ?“ Efficient ”– Special kernel optimizations to minimize performance overhead of capturing historical data – Stored pressed form in tablespaces to minimize storage requirements – Completely transparent to applications – Easy to set up Copyright ? 2009, Oracle. All rights reserved. 19 - 4 Flashback Data Archive: Overview Original data in Undo data DML operations buffer cache Flashback data archives stored in tablespaces 1 year 2 years 5 years Example: Three flashback data archives with retention of: For retention requirements exceeding undo FBDA Copyright ? 2009, Oracle. All rights reserved. 19 - 5 History or archive tables: - Compressed storage - With automatic digital shredding Flashback Data Archive: Architecture Buffer cache DML changes used by FBDA Old values Undo FBDA Flashback data archives 123 Copyright ? 2009, Oracle. All rights reserved. 19 - 6 Preparing Your Database ? Create one or more tablespaces for data archives and grant QUOTA on the tablespaces. ? Gr