Have a sneak peek of my book

Do you want to have a sneak peek of my book “Oracle 12c Backup and Recovery Survival Guide” I wrote with my good friend Aman Sharma? If yes, you can download the chapter 1 of the book as a demo Continue reading Have a sneak peek of my book

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, Continue reading LOGGING or NOLOGGING, that is the question – Part VIII

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 Continue reading LOGGING or NOLOGGING, that is the question – Part VII

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 Continue reading LOGGING or NOLOGGING, that is the question – Part VI

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. Continue reading LOGGING or NOLOGGING, that is the question – Part V

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 Continue reading LOGGING or NOLOGGING, that is the question – Part IV

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 Continue reading LOGGING or NOLOGGING, that is the question – Part III

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, Continue reading LOGGING or NOLOGGING, that is the question – Part II

LOGGING or NOLOGGING, that is the question – Part I

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 Continue reading LOGGING or NOLOGGING, that is the question – Part I

Differences between UNDO and REDO

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 Continue reading Differences between UNDO and REDO