pr*******@netscape.net (PR) wrote in message news:<d9**************************@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