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

On Sat, 2 Aug 2003 20:37:42 +0200, Anton Buijs <remove_aammbuijs_at_xs4all.nl> wrote:

> |
>
> You are right. I varied the value of log_checkpoint_timeout in my
> playground
> database and the status active becomes inactive after a period of time
> that
> is related to the timeout period. Lgwr is choosing priorities as you
> described. I get the impression it also depends on the load on the db. My
> tests where the only active sessions. When I do some (update) work the
> active status disappears also much quicker.
> Thanks.

It should be pointed out, however, that setting L_C_TIMEOUT is not a particularly good idea. In 8i, you have L_C_INTERVAL and FAST_START_IO_TARGET to work with to make instance recovery time extremely predictable. And in 9i, you have FAST_START_MTTR_TARGET to use, which internally gets converted into settings for _IO_TARGET and _INTERVAL -but not for _TIMEOUT. Which gives the game away: _TIMEOUT is not particularly useful in limiting instance recovery times in a predictable fashion.

In the absence of _TIMEOUT, behaviour is as I described earlier: another log switch will cause the original log's status to be updated.

~QM Received on Sat Aug 02 2003 - 20:06:58 CDT