Oracle Flashback-Fighting
1.Flashback queryDepend on:content in undo tablespace
1.1Base syntax:
1: SELECT ... FROM ... AS OF TIMESTAMP TO_TIMESTAMP('...','yyyy-mm-dd hh24:mi:ss')
1.2Flashback table
Hints:Row movement must be enabled on the tables needed to be flashback.
1:> Use Flashback table
1: FLASHBACK TABLE XXX TO TIMESTAMP('...','yyyy-mm-dd hh24:mi:ss')
Warning:If there exist foreign key constraint,maybe operator would flashback not only one table
1.3Flashback version query
Base:Virtual columns:VERSIONS_STARTSCN,VERSIONS_ENDSCN,VERSIONS_STARTTIME,VERSIONS_ENDTIME,
VERSIONS_XID(type RAW,transaction> Syntax:
1: SELECT 2: column1,column2,..., 3: VERSIONS_XID,VERSIONS_STARTTIME,VERSIONS_ENDTIME,VERSIONS_OPERATION 4: FROM 5: VERSIONS BETWEEN TIMESTAMP TIMESTAMP1 AND 6: TIMESTAMP2 7: WHERE
1.4Flashback transaction
Base:Based on flashback version query.
The dbms will provide the undo SQL commands to flashback the specified transaction operations
Involved Data Dictionary Table:FLASHBACK_TRANSACTION_QUERY(XID,…,OPERATION,ROWID,UNDO_SQL)
Flashback transaction manually(Get the undo_sql and execute it yourself):
1: SELECT OPERATION,UNDO_SQL FROM FLASHBACK_TRANSACTION_QUERY WHERE XID=hextoraw('xxxxxxxxxxxxxxx'); Flashback transacion with package of dbms:
1: execute 2: dbms_flashback.transaction_backout 3: (-numtxns=>2,-xids=sys.xid_array('0900010059100000','02000700920F0000',-options=>dbms_flashback.cascade);
2.Flashback deletion(drop only)
Depend on:recyclebin(renaming table)
2.1Performing flashback deletion
P1:flashback drop feature is enabled default.So tables dropped by users are put into recycle bin.
You should confirm it so that log in as the owner of table and “show recyclebin”
P2:
1: flashback table xxx to before drop
3.Flashback Database
Depend on:flashback log
3.1Enable flashback database feature
P1:Set FRA location
P2:Set the> P3:Set flashback retention
P4:Restart Database instance to mount
P5:
1:> P6:
1:>
3.2Flashback Database
P1:Restart database instance to mount
P2:
1: FLASHBACK DATABASE TO TIMESTAMP/SCN XXX P3:
1:>
4.Flashback Data Archive(FDA)/Total Recall
Base:
Create a tablespace to store flashback log data so that users can execute flashback query successfully
during retention period.
4.1Enable FDA on a table
P1:Create a tablespace
1: CREATE TABLESPACE FDA DATAFILE 'fda1.dbf'>
P2:Create a fda>
1: CREATE FLASHBACK ARCHIVE fla1 TABLESPACE FDA RETENTION 7 year; P3:Grant appropriate privilege to fdauser
1: GRANT FLASHBACK ARCHIVE ON fla1 TO P4:Enable FDA on tables
1:>
4.2Disable FDA on a table
P1:
1:> P2:
1: DROP FLASHBACK ARCHIVE fla1;
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