Re: Why does an online redolog keeps active after checkpoint completion?

On Sat, 02 Aug 2003 14:22:25 GMT, Yago <yago2003_at_terra.es> wrote:

> Well, if your database is in Archivelog mode, after the log switch the
> online redo log is still active until its archiving process is finished.
>
> Regards,
>
> Yago
>

Incorrect. A log file has a status of active until its been checkpointed. That's one thing. Then it has a status of archived or unarchived. That's another thing. You can see that quite clearly in v$log... there's a column called STATUS ('active', 'inactive' or 'current') and another column entirely called 'ARCHIVED' (yes or no). Two different causes, two different scenarios. And your suggestion that the one affects the other is quite wrong.

The source of confusion for the original poster is simply that in 8i (if not in 8.0??) Oracle made a change: a log isn't inactive until it's been switched away from, been checkpointed *and the next log's been switched away from, too*. Which means our friend needs to switch twice before the original log appears as inactive.

It's been documented for a while, too.

~QM

> "Anton Buijs" <remove_aammbuijs_at_xs4all.nl> wrote in message
> news:3f2ad39d$0$49098$e4fe514c_at_news.xs4all.nl...
>> I found this behaviour that I don't understand
>> Oracle V8.1.7.3 EE 64-bit on HP-UX 11i. (and in may playground Windows
>> 98,
>> V8.1.5 Personal Edition).
>>
>> When a log switch occurs the redolog status goes from current to active
>> (v$log. status) and a checkpoint occurs.
>> When I check v$datafile_header.checkpoint_change# and checkpoint_time I
> can
>> see the checkpoint has completed.
>> But the redolog status keeps active, even minutes later.
>> After 'alter system checkpoint' it is immediately inactive.
>>
>> Why does the status of the redolog keeps active so long?
>> I thought it was no longer needed (status becomes inactive) when the
>> checkpoint completes?
>> The impact can be that I still need that redo in the unfortunate event I
>> loose this redolog group completely (which ofcourse should never happen,
> but
>> if all that never should happen really never happended we would not have
> so
>> much fun in this newsgroup).
>>
>>
>
>
>

-- 
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/