Re: archive log curr v. switch logfile

The 'ALTER SYSTEM ARCHIVELOG CURRENT' is the preferred one that should be used for backup scripts.

The reason being, if you have noticed when you do an 'ALTER SYSTEM SWITCH LOGFILE', you get the prompt back immediately. This command performs a database checkpoint, switches to the next log, signals the archiver to copy the logfile to the archive destination, and returns the prompt. Mind you, this command does not wait for the archive to complete. As the command indicates, it only performs a log switch. Hence, you might come across backup scripts which does an 'ALTER SYSTEM SWITCH LOGFILE' and then does a SLEEP for some time, thus allocating some time for the Archiver to finish archiving. Whereas, an 'ALTER SYSTEM ARCHIVE LOG CURRENT' does all of the above, but does not return back to the prompt until the archive is complete.

Also, 'ALTER SYSTEM SWITCH LOGFILE' archives only the current thread. Whereas the 'ALTER SYSTEM ARCHIVELOG CURRENT' needs a thread to be specified and If you miss the thread parameter, Oracle archives all redo log file groups from all enabled threads, including logs previous to current logs.

Hope this helps.

Raj

                                                                                                                               
                    "Baker, Barbara"                                                                                           
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                    March 29, 2002 11:23 AM                                                                                    
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Can anyone tell me the difference between
           alter system archive log current
and
           alter system switch logfile

(Seems they both perform checkpoint and both switch a log file).
Is one preferred over the other for purposes of switching log files prior to
applying to a standby database?

Thanks for any insights.

Barb

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