Re: Schema changes on on large tables
Date: 15 Sep 2004 06:18:37 -0700
Message-ID: <ed737cdd.0409150518.66547355_at_posting.google.com>
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 - 15:18:37 CEST