Re: RAM based database management

Hi Femi,

Given that Oracle keeps everything in the SGA why do you want to use your own RAM drive? I suspect that doing so can cause memory contention problems. In fact one of the cautions in the various books on Oracle tuning is not to make your SGA so big that the operating system will swap out part of the Oracle SGA. By creating a RAM drive you are, in effect, making an assumption that you can manage memory better than Oracle does. creating an oversized SGA.

When you say the rollback segment keeps blowing up I assume that you mean it is out of space. There are entire chapters about managing rollback segments. The quick and dirty solutions are:         

1. Increase the size of the rollback segment
2. Assign the transaction to a specific rollback segment large enough to handle it.
3. Increase the frequency of your commits so that less data need be stored in the rollback segment.
4. Examine your select statements to see if you can eliminate redundant order by clauses etc.

Unless you are running batch updates or loads of large tables the contents of a rollback segment should be well under 10 minutes old. In fact, in a typical OLTP environment it should be rare to have data in rollback segment that is much more than a minute or two old.

Regards

Jerry

Femi Aderounmu wrote:
>
> Does anyone have experience with RAM drive based databases. I am new to
> Oracle and I am trying to create a database with the data and rollback
> files located in RAM drives.
>
> I create a RAM drive, then use a SQL code file to automatically load
> datafiles on my hard drive into the RAM drive. The main problem I have
> encountered:
>
> 1)The Rollback segment keeps blowing up. How can I safely delete it or
> reduce it's size during operation?
>
> I understand that the rollback file should be kept on the hard drive but
> I care little for old data. The data becomes useless after about 10
> minutes anyway, since the application is a semi-real time application.
>
> --
> Femi
> New Jersey
> --
 

-- 
Jerry Gitomer         	ICT Group
jgitomer_at_ictgroup.com	Langhorne PA
jgitomer_at_p3.net 	Opinions are mine not those of ICT Group