Re: spreading my wings -- looking for some recommdations/best practices

Sorry for late reply, some problems with ISP access down this end...

Q:
Suppose I alter a symbolic link so that it points to directory B (instead of
directory A) precisely as an archive is actually being written (and hence
the link is in use)?
I thought, and you seem to agree, that the entire archive will end up safe
and sound in destination A. But, when that archive is finished, does the
link become 'unused', and hence the change to it takes effect? Would that
mean the *next* archive gets sent to destination B?

A:
As far as I know, it all depends on what Oracle does with the archive directories. That I suppose can only be confirmed by looking at the source
code. IF they open the directory as a file, they might be seeing old metadata there.

The normal effect would be for the current archive file to be finished and closed by Oracle with close(). This would then free the file unit back to the OS. Any subsequent open of a file would grab whatever is now in the directory definition as far as that link goes.

It's not as if the old definition is still there for the OS to grab, it's
just that any file unit still open would assume the old definition - a file unit takes a snapshot of the file metadata at open() time and keeps
it. Any new file units (be they via open of existing file or create new file) would grab the current definition of the link from the directory file itself, whatever it might be at open() time.

There are some minor variations on this depending on the program itself doing a close(), or an unlink(), or other system calls that imply a close
of the file unit. But the most common sequence of events would be as I

described above. Having said that, who knows what is in Oracle's code... Received on Wed Oct 27 2004 - 00:08:24 CDT