0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez How to find Sessions Generating Lots of Redo To find sessions generating lots of redo, you can use either of the following methods. Both methods examine the amount of undo generated. When a transaction generates undo, it…
Category: Redo Logs
LOGGING or NOLOGGING, that is the question – Part VII
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez Redo Logging I/O-Related Wait Events There are a number of Wait Events that happen during Redo Logging activities and most of them are I/O-related. The two most important ones are ‘log file parallel write’ and ‘log file…
LOGGING or NOLOGGING, that is the question – Part VI
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez TIPS USING NOLOGGING MODE DIRECT PATH INSERT To use Direct Path Insert use the /*+ APPEND */ hint as follow: INSERT /*+ APPEND */ into … SELECT … When direct path insert is used oracle does the…
LOGGING or NOLOGGING, that is the question – Part V
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez REDUCING REDO GENERATION TIPS While Backing Up As mentioned in the redo generation and recoverability section, user managed backups could generate a lot of redo. The best way to eliminate this problem is to use RMAN. RMAN…
LOGGING or NOLOGGING, that is the question – Part IV
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez Disabling Redo Generation (NOLOGGING) The NOLOGGING attribute tells the Oracle that the operation being performed does not need to be recoverable in the event of a failure. In this case Oracle will generate a minimal number of…
LOGGING or NOLOGGING, that is the question – Part III
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez Important points about LOGGING and NOLOGGING Despite the importance of the redo entries, Oracle gave users the ability to limit redo generation on tables and indexes by setting them in NOLOGGING mode. NOLOGGING affect the recoverability….
LOGGING or NOLOGGING, that is the question – Part II
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez Redo Generation and Recoverability The purpose of redo generation is to ensure recoverability. This is the reason why, Oracle does not give the DBA a lot of control over redo generation. If the instance crashes, then…
LOGGING or NOLOGGING, that is the question – Part I
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email By Francisco Munoz Alvarez Introduction The main question about NOLOGGING I hear all the time is: does creating a table with the NOLOGGING option means there is “no generation of redo ever”, or just that the initial creation operation has no…
Differences between UNDO and REDO
0 Shares 0 Facebook 0 Twitter 0 Linkedin 0 Facebook-messenger 0 Whatsapp 0 Email To clear this question we have this table: UNDO REDO Record of How to undo a change How to reproduce a change Used for Rollback, Read-Consistency Rolling forward DB Changes Stored in Undo segments Redo log files Protect Against Inconsistent reads…