Re: Implementing Archiving of Redo logs some more questions (Sybrand and Howard)

On Sat, 15 Feb 2003 00:31:52 +0000, mokat6 wrote:

> May I thank both Gentlemen Sybrand and Howard for their fast response.
>
> But I see differences in the answers of 2 questions:
>
>> 4- In case of recovery operation where is the database looking for
>> the log files? In my case location 1, 2 or both as long as he find the
>> right log?
>
> Sybrand: c) is the right answer
>
> Howard: In location 1, but if it can't find the log it needs there,
> it will flip over to location 2 automatically to see if it can find it
> there. This behaviour was intended to happen in 8i, but didn't (!!),
> but it works fine
> in 9i.
>

Well, Sybrand can defend himself just fine. But simply saying 'it looks in both locations' is a bit daft: if it finds it in the first location, why on earth would it proceed to waste time looking for the same file in the second location?

Which is why Sybrand is not wrong (it *has* the capability to look in both) but it's not totally accurate either.

>>
>> 5- According to the default parameter settings must one location be
>> available for archiving. I gues it does not matter which one of the
>> two?
>>
> Sybrand?: It does not matter which one of the two
>
> Howard: By default, destination 1 is mandatory and all others are
> optional.

I'm going to back off on this one. Reading the Oracle Docs on 9.2 again, they state that with three OPTIONAL destinations (and OPTIONAL is the default), but a MIN_SUCCEED_DEST of 1 (which is also the default, and minimum, value) then any one of the three possible destinations will be acceptable. Which makes Sybrand correct.

I was getting confused with the older parameters LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST, where LOG_ARCHIVE_MIN_SUCCEED_DEST could then be set to either 1 or 2 and (here's the thing) if you'd set both _DEST and _DUPLEX_DEST but set MIN_SUCCEED_DEST to only 1, then _DEST was compulsory, and _DUPLEX_DEST was optional, as the following snippet from the 8i documentation states:

"* If you are using LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST and automatic archiving is enabled, a value of 1 [for MIN_SUCCEED_DEST] specifies that the destination specified in LOG_ARCHIVE_DEST must succeed."

Regards
HJR Received on Fri Feb 14 2003 - 22:28:17 CST