Backup & Recovery

FLASHBACK PLUGGABLE DATABASE now available in #Oracle 12cR2

With the current release 12.2, flashback can be done on the PDB layer. As a prerequisite, the database must be put into local undo mode. That means that each PDB has its own undo tablespace. Some other 12.2 features like hot PDB cloning also require this, so chances are that most 12cR2 multitenant databases will be using that mode.

How to speed up Data Pump Import by suppressing redo generation in #Oracle 12c

With your database in archive log mode, a Data Pump Import may be severely slowed down by the writing of much redo into online logs and the the generation of many archive logs. A 12c New Feature enables you to avoid that slow down by suppressing redo generation for the import only. You can keep the database in archive log mode the whole time. Let’s see that in action!

First without the new feature:

How to do PDB PITR in #Oracle 12c

A logical error happened in one Pluggable Database. A PDB Point-In-Time-Recovery rewinds it while the others remain available and stay as they are.

Logical error in PDB2

Logical error in PDB2

How to use DURATION with RMAN backups in #Oracle

The DURATION clause enables you to reduce the performance impact of RMAN backups respectively it sets a certain time limit for the backup.

Let’s suppose your RMAN backup takes one hour now and you take it online while end users work with the database. This reduces the performance impact of the online backup by half approximately:

RMAN> backup duration 02:00 minimize load database;

The first two digits are hours, the second two digits are minutes. Above command tells RMAN to spend 02 hours and 00 minutes with the backup that takes normally one hour. That way, RMAN gets throttled down, causing roughly half the load on the system than otherwise.

How to resolve media failures with the Recovery Advisor in #Oracle

Error messages are showing up because files have been damaged? Database Recovery Advisor to the rescue!

RMAN old feature: Restore datafile without backup

Say I have created a new tablespace recently and did not yet take a backup of the datafile. Now I lose that datafile. Dilemma? No, because I can do an ALTER DATABASE CREATE DATAFILE. Sounds complex? Well even if I wouldn’t be aware of that possibility, a simple RMAN restore will work – as if there were a backup:

Table Recovery in #Oracle 12c

You can now restore single tables from backup! It is a simple command although it leads to much effort by RMAN. See it as an enhancement over a ‘normal’ Point In Time Recovery:

Point In Time Recovery

Point In Time Recovery

After a full restore from a sufficiently old backup, archived logs are being applied in direction of the presence until before the logical error. Then a new incarnation comes up (with RESETLOGS) and the whole database is as it was at that time. But what if it is only a dropped table that needs to be recovered? Enter the 12c New Feature:

Multisection Backup for Image Copies

A nice Oracle Database 12c New Feature enhances the multisection backup, introduced in 11g: You can use it now for image copies also!

Multisection Backup with Image Copy

Multisection Backup with Image Copy

New 12c Default: Controlfile Autobackup On – But only for Multitenant

This a a little discovery from my present Oracle Database 12c New Features course in Copenhagen: The default setting for Controlfile Autobackup has changed to ON – but only for Multitenant, apparently:

Restore datafile from service: A cool #Oracle 12c Feature

You can restore a datafile directly from a physical standby database to the primary. Over the network. With compressed backupsets. How cool is that?

Here’s a demo from my present class Oracle Database 12c: Data Guard Administration. prima is the primary database on host01, physt is a physical standby database on host03. There is an Oracle Net configuration on both hosts that enable host01 to tnsping physt and host03 to tnsping prima