Re: Rollback Segments

Hi Carlos,

        Adding more rollback segments won't help. There are three alternatives (one of which may not apply in your case):

1. Increase maxextents (I think you are at the limit for NT)
2. Increase initial and/or next extents from 50K to at least 100K.
3. Create a very large rollback segment and then assign the big transaction to it using the SET TRANSACTION command.

        My personal preference is the third alternative since, in most cases, only one very large rollback segment is needed and it is, IMHO, more desirable to have less disk space tied up.

regards

Jerry

calberto_at_my-dejanews.com wrote:
>
> Hi all!
>
> I'm having problems with rollback segments in Oracle. We, in our company, have
> an long-running application (about 3 hours) which after 2 hours give us the
> following message :
>
> ORA 01555 - Snapshot too old .....
>
> The server currently has 16 rollback segments, which one with the following
> parameters :
>
> INITIAL - 50K
> NEXT - 50K
> OPTIMAL - DEFAULT (I suppose Oracle's default is NULL)
> MINEXTENTS - 2
> MAXEXTENTS - 121
>
> Is the solution increase the NEXT parameter?
>
> Beyond this, I have some doubts :
>
> 1) I have manually put all these segments online, but when the machine
> rebooted (for other reasons), Oracle have put some of them offline. Why?
>
> 2) Since my OPTIMAL parameter is the default, when Oracle will release the
> extents of the segments?
>
> 3) All these rollback segments are in one tablespace which has 2 datafiles of
> 20 MB each, but there is only 2 MB free. Is this related with the problem?
>
> We have Oracle 7.3 running on NT 4.0.
>
> Thank in advanced,
>
> Carlos
>
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--

Jerry Gitomer         	ICT Group
jgitomer_at_ictgroup.com	Langhorne PA
jgitomer_at_yahoo.com 	Opinions are mine not those of ICT Group