Re: what is the different?

alter system switch logfile switches between current online redo logs. It (should) always work.

alter system archive log current will archive the (current) redo log. It thus requires all of the prerequisites for archiving redo logs.

Most likely causes for the second command to fail

1. you are not in archivelog mode
2. you have run out of space in your archive log destination.

The error message in the alert log will tell you what the problem is.

IMO you should also not usually need to issue the second command since oracle will quite happily archive redo logs for you automatically.

--

Niall Litchfield
Oracle DBA
Audit Commission UK
"Cheong" <leslie_hk_at_hotmail.com> wrote in message
news:3b113326_at_newsgate.imsbiz.com...


> Can anyone tell me what is the different of the following two commands

>

> alter system archive log current

> alter system switch logfile

>

> and why the first command always produce and error a message fail to

 arhive


> log ... in alert log file.

>

> Thanks in advance

>

> Antony

>

>