Re: most expeditious way to update a large number of rows

Brian Peasland wrote:
> How can you make any assessment of this individual's online redo log
> size? Did I miss where the redo generation rate was specified? In one
> system where a 100MB online redo log size is appropriate, other systems
> may find 1MB more appropriate. The size of the online redo logs should
> be predicated by the following:
>
> 1. What is the redo generation rate?
> 2. If a Standby database is employed, the type of Standby configuration
> which dictates how transactions are shipped to the Standby database. How
> does this play into your online redo log size?
> 3. How often will archived redo logs be written to tape or other
> destination not residing on the database server?
> 4. In the absence of Standby configuration, what is the SLA for data loss.
>
>
> One wants to size their redo logs appropriately so that the redo gets
> archived and copied to a safe location frequently enough so as to meet
> the defined SLA for that system. However, one does not want to switch
> too frequently so as to put unnecessary stress on the system. I have
> some systems which only generate 50MB of archived redo each day. Why
> would I want a 100MB online redo log on that system? I have other
> systems which can generate 1GB of redo per minute. IMO, no one size fits
> all, which is why I enjoy the fact that Oracle lets me determine an
> optimal size for the online redo logs on a database-by-database basis. :)
>
>
> Cheers,
> Brian

Brian,

I have 5 redo log groups, each is 10MB. I cannot (easily) add more (the database was created with a max. of 5.)

1. Roughly 200MB of redo is generated daily.
2. Maximum availability. Physical standby. ARCHIVE_LAG_TARGET set.
3. Database and archived redo logs backed up nightly with RMAN (and written to tape).

In your estimation, what's the ideal size/number of log groups?

Thanks for your help, Brian!
Myles Received on Mon Oct 16 2006 - 12:57:35 CDT