TOI

How Partial Indexing helps you save space in #Oracle 12c

partialhttps://uhesse.files.wordpress.com/2016/12/partial1.png?w=600&h=580 600w, https://uhesse.files.wordpress.com/2016/12/partial1.png?w=150&h=145 150w" sizes="(max-width: 300px) 100vw, 300px" />

Over time certain partitions may become less popular. In 12c, you don’t have to index these partitions anymore! This can save huge amounts of space and is one of the best 12c New Features in my opinion. Really a big deal if you are working with range partitioned tables where the phenomenon of old ranges becoming unpopular is very common. Let’s have a look, first at the problem:

How to change RANGE- to INTERVAL-Partitioning in #Oracle

set_intervalhttps://uhesse.files.wordpress.com/2016/11/set_interval.png?w=578&h=600 578w, https://uhesse.files.wordpress.com/2016/11/set_interval.png?w=144&h=150 144w" sizes="(max-width: 289px) 100vw, 289px" />

An existing RANGE partitioned table can easily be changed to be INTERVAL partitioned with the SET INTERVAL command. My table has been created initially like this:

Enjoying a great conference at the #DOAG2016

It’s DOAG season again and the Oracle Community is having a good time here! That includes me, presenting about the  Multitenant architecture:

doag2016https://uhesse.files.wordpress.com/2016/11/doag2016.jpg?w=1240&h=930 1240w, https://uhesse.files.wordpress.com/2016/11/doag2016.jpg?w=150&h=113 150w, https://uhesse.files.wordpress.com/2016/11/doag2016.jpg?w=300&h=225 300w, https://uhesse.files.wordpress.com/2016/11/doag2016.jpg?w=768&h=576 768w, https://uhesse.files.wordpress.com/2016/11/doag2016.jpg?w=1024&h=768 1024w" sizes="(max-width: 620px) 100vw, 620px" />

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 safeguard against malicious developers in #Oracle 12c

AUTHID_CURRENT_USER can be misused by developers. The new object privilege INHERIT PRIVILEGES ON was introduced in 12c to prevent that. I start with a demo to explain the problem that the new features solves. The playground:

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 reinstate the old Primary as a Standby after Failover in #Oracle

You have done a failover to your Standby database so it becomes the new Primary. It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. The old Primary must have been running in flashback mode before the failover. The playground:

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!