| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Usenet -> c.d.o.server -> Re: Backup control file
On Mon, 01 Feb 1999 21:35:55 GMT, Roland Cycan
<Roland_Cycan_at_yahoo.com> wrote:
>In a backup and recovery book I've been looking at it is
>suggested that control files be backed up after a create, alter,
>or drop on any datafile, table, or tablespace. It doesn't seem
I doubt it stated to perform backup controlfile after creating/altering/droping a *table*, as this operation does not change database structure recorded in a control file!
>to state explicitly that these events are not recorded in the
>redo logs, although it does leave that impression.
>
>Are these events recorded in the redo logs? If so, is it really
>worth the effort to backup the control files after each of these
>events? If not, why on earth are they not recorded in the redo
>logs?
All of the events you mention *are* recorded in redo logs, including the addition of a datafile to the database. This, however, does not mean the roll forward proces of database recovery will create this datafile. It will only make changes to the controlfile to indicate the new datafile in a database structure. But if this datafile is not present at the original location the recovery process will fail. In this case you'll have to create the file manualy and repeat the recovery proces.
A regular "binary backup" of the controlfile could not be of much use in such a situation. But if you do "backup controlfile to trace" you'll get the ascii file with the complete physical structure of a database and this can help you in determining the location and the size of newly created file, so yes, it is not a bad idea to backup controlfile (to trace) anytime you modify a database physical layout.
>And what about create, alter, or drop on any other object, such
>as a function or view? Are these recorded in the redo logs?
Yes they are and they will hapyly be recreated during database recovery. And no, there is no need to backup controlfile after creating/modifying/droping any of them.
HTH,
Jurij Modic <jmodic_at_src.si>
Certified Oracle7 DBA (OCP)
 |
 |