Re: Schema changes on on large tables

priisberg_at_netscape.net (PR) wrote in message news:<d95b480f.0409132303.291b66f9_at_posting.google.com>...
> Hi,
> I have a basic question on schema changes performed on populated tables.
> Should I prepare for big roll back area and so on for both of these changes:
> ALTER TABLE ADD COLUMN
> ALTER TABLE ALTER COLUMN
> Table contain abt. 40 mill records
>
> Appriciate the help, as i am just DBA stand in in my project:-)

ALTER TABLE ADD COLUMN As far this is only a change in Oracle's data repository there is nothing to concern about rbs sizing = fast.

ALTER TABLE MODIFY COLUMN (you mean)

generally, no overhead if you keep the sizes or extend them = fast if you shrink the sizes there's some validation that could take a while, but nothing to concern about regarding rbs.

RBS will come into play when you have to update your new/changed column.
I prefer several RBS split in one RBS per tablespace , enough data files with autoextend (but with max. size limit, say 2 Gb) so the system can choose ANY rbs to end the transaction successfully.

hope that helps

yk Received on Wed Sep 15 2004 - 08:18:37 CDT