Re: MVIEW on-demand refresh - rollback space issue

        No there is no way to split refresh of 1 mview to many transactions. However, I can give you some things to look at:

• if you are using refresh group and dbms_refresh.refresh, all mviews in it are refreshed in one transaction (for data consistency). If this is your case, try refreshing the big mview with dbms_mview.refresh instead (but be aware of consistency of data - foreign keys, etc).
• if you changed "most" of the records, you may benefit from complete refresh. Complete refresh makes "truncate" (which is DDL and commits) and then insert for all rows in the mview. I've seen this to be better on network traffinc if there are updates of "most" of the rows. It will be better on rollback also (truncate is lightweight on undo, insert is quite lighter than update also). Beware that the table is practicaly EMPTY until the refresh completes, so user will not see any data. Also if you abort the refresh (e.g. network problems) - you cannot rollback, because of the truncate. Complete refresh is made with dbms_mview.refresh(mview_name, 'C')
• try refreshing more often, when you have less data updted (this is obvious, but depends on your BUSINESS needs)

Yavor

On Tue, 21 Feb 2006 20:24:11 +0200, Mindaugas Navickas <mnavickas_at_yahoo.com> wrote:

> Hi,
>
> Platform Oracle 9.2.0.5 on HP-UX
> Error(s):
> ORA-12008: error in materialized view refresh path
> ORA-01562: failed to extend rollback segment number 2
> ORA-01650: unable to extend rollback segment RBS_1 by 125 in tablespace
> ROLLBACK
>
> A big table is updated during a day on primary location. This table has
> MV log
> created - using PK.
> Once a day changes to this table has to be propagated to a remote site
> (on-demand replication based on PK).
>
> Most of times replication process works fine, however, there are times
> when
> larger number of rows are updated. Then replication fails with errors
> above.
> I know that most straightforward way would be to increase rollback
> tablespace
> size on remote site, however, we are short of disk space on that site and
> growing rollback tablespace (already 1.2G) just to accommodate this case
> it
> doesn't makes much sense (most of transactions on that database are
> small).
>
> <b>Is there a way of splitting replication transaction into number of
> transactions?</b>
>
> May be I am looking for something what does not exists, however, I hope,
> that
> others might faced similar problem and can share how they solved that.
>
> Thank you
> Mindaugas Navickas
> DBA, OCP 10g, 9i, 8i
>
>
>
>
>
>
>
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