Heartbleed & Oracle

By now I think the whole world has heard about the heartbleed bug and the seriousness of it all. So how does it affect Oracle? According to the Oracle support site there are a number of products that may be affected. Here’s a list: Products which are vulneralbe but have patches available:

Products still […]

Heavy swapping observed on system in last 5 mins

As I was refreshing a dev database and checking out the alert log I noticed the following message:

To make sure it wasn’t to do with the refresh I looked at other database alert logs and history and found that this message has been constantly appearing in all logs for the last 6 months […]

Disable Parallel Query for CDB_ Views

During my investigation in cdb$view bug I’ve come across the hidden parameter “_px_cdb_view_enabled” which can disable parallel query for cdb_ views. Lets see it in action. Leave at default and run query over cdb_data_files.

Now lets disable it by setting it to false and see what happens.

As you can see by the […]

Patch 17552800: DATABASE PATCH SET UPDATE 12.1.0.1.2

Applying this patch to a single instance multitenant database. As with almost every patch download latest Opatch and unzip into Oracle Home.

Unzip the patch file and run the prereq checks

Shutdown all instances and listeners associated with this instance.

Now lets run opatch.

All looks good. Time to start up […]

PDB Close Database Bug

Just going through some HA testing on our multitenant RAC Database and we hit the error below when trying to close the pdb on the second node while being logged into the first node.

Looking at the alert log on the second node we see.

On Metalink we see this is a known […]

CDB$VIEW

You may be familiar with the data dictionary views USER_, ALL_ and DBA_. Oracle 12C introduces the CDB_ views to cater for multitency. Looking a little deeper these CDB_ views are generated from a function called CDB$VIEW. Lets use CDB_USERS as an example.

We can see from the above CDB$VIEW(“SYS”.”DBA_USERS”). This looks like some […]