Oracle Redo Log Recovery Data simulation experiment

A system environment:

1. Operating system: Oracle Linux 5.62, database: Oracle 11g two Oracle redo log: [Simulated media recovery]1. Turn off database archiving mode: [[email protected] ~]$ sqlplus/nologsql*plus:release 11.2.0.1.0 Production on Mon Feb 6 23:49:30 2017Copy  Right (c) 1982, Oracle. All rights reserved. Sql> Conn/as sysdbaconnected.sql> show Useruser is "SYS" sql> shutdown immediatedatabase closed. Database dismounted. ORACLE instance shut down. sql> start mountsp2-0310:unable to open File "Mount.sql" Sql> startup Mountoracle instance started. Total System Global area 830930944 bytesfixed size 2217912 bytesvariable size 478152776 byte Sdatabase buffers 348127232 Bytesredo buffers 2433024 bytesdatabase mounted.     sql> ALTER DATABASE Noarchivelog;database altered. 2. Create test table Space hltest:create tablespace hltest datafile ' hltest.ora ' size 5M autoextend on NEXT 1M MAXSIZE UNLIMITED Default  Storage (initial 128K next 1M pctincrease 0);  3. Create test user and test table: Drop user HL cascade; Create User HL IDentified by HL default tablespace hltest;  Grant Connect,resource to HL; Conn Hl/hl;  CREATE Table A (a number)----creating tables and populating the data.    Begin for I in 1..100000 loop insert into a values (i);   End Loop;    End  Commit 4. Copy Test.ora to Test1.ora file.    5. Insert into a SELECT * from A; --200,000 article 6. Close the database shutdown Immediate7. Swaps the file Test1.ora with the Test.ora name. 8. Start the database again sql> shutdown immediatedatabase closed. Database dismounted. ORACLE instance shut down. Sql> Startuporacle instance started. Total System Global area 830930944 bytesfixed size 2217912 bytesvariable size 478152776 byte Sdatabase buffers 348127232 Bytesredo buffers 2433024 bytesdatabase mounted. Ora-01113:file 8 Needs Media recoveryora-01110:data file 8: '/u01/app/oracle/product/11.2.0/dbhome_1/dbs/ U01apporacleoradataorclhltest.ora ' 9. The media recovery:sql> recover database; Media recovery complete. sql> ALTER DATABASE open;D Atabase altered. Experience: Oracle online redo log (online REDO log FILE) is primarily used for databaseMedia recovery, such as corruption of data files.          The archive log (archived log FILE) is actually a backup of the online log, after all, the online log space is limited and can only hold a certain amount of time to redo the log data. The combination of archived logs and full-Library backup files restores better results.
The next article will perform a simulation of the data table removal via Rman for recovery.

Oracle Redo Log Recovery Data simulation experiment