Re: Difference between "alter database archivelog" and "alter system archive log start"

Robert,

The first of these commands (i.e., alter database archivelog;) starts the archiving process. This causes the Oracle database to require that the redo logs are archived before they are reused (in their normal circular queue manner). This does not actually do the archiving. If you do not archive the logs using automatic archiving (i.e., alter system archive log start;) or manually archive them (i.e., alter system archive log all;) then your instance will halt when the last redo log group is filled (until you archive the redo logs). Usually, you will put the automatic archiving parameters in your init<sid>.ora file and not worry about automatic or manual archiving (this will actually start up automatic archiving at instance startup). The following init<sid>.ora parameters will do the trick. You obviously need to modify them for your purposes.

log_archive_dest                    = G:\Orawin95\database\backup\orcl\arch
log_archive_format                = "Log_Archive_ORCL%S.arc"
log_archive_start                   = true

The first of these is the directory into which you wish Oracle to copy the redo logs. The second of these is the file format (see the Oracle Server Reference manual for this). The last of these actually starts the automatic copying of the redo logs to the log_archive_dest directory.

I hope that this has been helpful. This is indeed a confusing situation. When I first started, I got it wrong.

Larry

Robert Chung wrote in message <3584bc52.84488_at_news.mindspring.com>...
>
>When you issue "archive log list" command from the Server Manager, you
>get output that looks like this:
>
> SVRMGR> startup mount exclusive;
> ORACLE instance started.
> Total System Global Area 5508628 bytes
> Fixed Size 45584 bytes
> Variable Size 4529156 bytes
> Database Buffers 409600 bytes
> Redo Buffers 524288 bytes
> Database mounted.
>
> SVRMGR> archive log list;
> Database log mode No Archive Mode <---- LINE (1)
> Automatic archival Disabled <---- LINE (2)
> Archive destination %ORACLE_HOME%\database\archive
> Oldest online log sequence 21
> Next log sequence to archive 22
> Current log sequence 22
>
>
>When I tried "alter database archivelog", it changed output in Line
>(1) to "Archive Mode", but it did not have any effect on Line(2). On
>the other hand, "alter system archive log start" changed output in
>Line (2) to "Enabled", but did not have any effect on Line(1). What
>is the difference between these two commands? What the heck is
>happening in the database system level? Thank you very much in
>advance.
>
>
>
Received on Mon Jun 15 1998 - 13:21:54 CDT