Blog Archives

LOGGING or NOLOGGING, that is the question – Part VIII

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,

Posted in General, Interview Tips, Monitoring, Questions, Redo Logs, Scripts, Tuning

LOGGING or NOLOGGING, that is the question – Part VII

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

Posted in Redo Logs

LOGGING or NOLOGGING, that is the question – Part VI

 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

Posted in Redo Logs, Tutorials, White Papers

LOGGING or NOLOGGING, that is the question – Part V

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.

Posted in Redo Logs

LOGGING or NOLOGGING, that is the question – Part IV

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

Posted in Redo Logs

LOGGING or NOLOGGING, that is the question – Part III

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

Posted in Redo Logs

LOGGING or NOLOGGING, that is the question – Part II

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,

Posted in Redo Logs