A performance deep dive into tablespace encryption

This is a run through of a performance investigation into Oracle tablespace encryption. These are the versions this test was performed on:

$ cat /etc/oracle-release
Oracle Linux Server release 6.8
$ /u01/app/oracle/product/ lspatches
24315824;Database PSU, Oracle JavaVM Component (OCT2016)
24006101;Database Patch Set Update : (24006101)

In this test I created an encrypted tablespace:

SQL> create tablespace is_encrypted datafile size 10m autoextend  (more...)

#Javaland 2017 wrap up

Yes – I did it again and attend Javaland conference in Phantasialand Brühl.

It was not easy this year to concentrate on the sessions because of the hottest march of the last 100 years. But the quality of the sessions beats the weather. Maybe again my invest in reading the abstracts and filter the sessions before the conference has payed off.

Day 1 Conference

Jens Schauderdocumentation & slides with AsciiDoc, Git, Gradle and Reveal.js


Using virt-install/KVM and kickstart to create lots of identical VMs quickly

In preparation for an upcoming talk about Oracle 12.2 I am planning on getting my feet wet with the Oracle 12.2 Sharding option. It seems to be a very interesting subject to get into, but like all new subjects, they can be intimidating at first due to their complexity. So why not use the instructions someone has already written down?

Oracle has a nice series of articles about Sharding. I found the Sharding (more...)

Python variable not defined

While working with a programming example for my students, I ran into an interesting run-time error when I changed their approach to importing Python’s random module. Here’s the raised error message:

Traceback (most recent call last):
  File "windowBouncingBalls.py", line 84, in 
    speed = [choice([-2,2]), choice([-2,2])]
NameError: name 'choice' is not defined

You raise the missing choice identifier when two things occur. The first thing requires you to use a standard import statement, like the (more...)

Enable HyperFIDO U2F Key on Linux

Recently, I bought the Hypersecu HyperFIDO K5 Key to help me secure access to several websites and services with U2F (“Universal Two-Factor Authorization”). This works fine on Windows, but with Linux things get a little complicated: The key isn’t accessible to all users by default. This has to be activated using udev rules, which is widely […]

Using VS Code for PL/SQL development

I've been using Sublime Text as my main editor for PL/SQL development for many years, but I'm now in the process of switching to Visual Studio Code (VS Code).

Some good reasons to use VS Code:
  • Multi-platform (Windows, OS X, Linux)
  • Free, open source
  • Lightweight, fast
  • Large ecosystem of extensions
  • Built-in Git support
  • Can be adapted to PL/SQL coding via a plsql language extension (syntax highlighting, go to/peek definition, go to symbol) and PL/SQL compilation (more...)

Little things worth knowing: Executing RDA on RAC

Result! I have finally been able to gather a complete RDA (Oracle Remote Diagnostic Agent) output on my 2 node RAC system. After consulting the relevant documentation on MOS-which is spread over at least 42 Doc IDs-I found them not to be very helpful to the degree that some of what I read is actually wrong or contradicting. I put together a short note, primarily to myself, to remind me of the process. I hope you find it useful, (more...)

New Events for Data Guard and Synchronous Redo Transport in 12c (2)

After the baseline has been established in the first part of this series it’s time to measure the effect of the network in this part. The second test will introduce an interesting feature: Using Linux’s own Traffic Shaper/Quality of Services module I will add a delay of 100ms to the Data Guard network interface card (NIC) to slow things down a little.

WARNING: this is of course a lab or VM-only situation. I can’t (more...)

Linux: keyring-password for wlan needed / legitimate wlan login

Each time i resume my notebook after a suspend to disk-cycle the connection to WLAN hangs with the following message:

 (Die Systemrichtlinien verhinder das Bearbeiten von Netzwerkeinstellungen für alle Benutzer / Enter password for default keyring to unlock)
I tried to fix this via network-manager with adding the hook at the checkbox "Alle Benutzer dürfen dieses Netzwerk verwenden", but this did not help at all.
The point is, that after resuming my login keyring wants (more...)

Oracle Linux Update from 7.2 to 7.3 crashes with uncorrectable CPU error

During the Upgrade of Oracle Linux 7.2 to 7.3 with “yum update”, when updating the microcode_ctl package, the system crashed and firmware reported an uncorrectable CPU error after reboot.

It turned out that the update of the package in combination with specific Intel CPUs causes the issue. In the meantime, there is a red hat bug and solution available.



  • https://community.oracle.com/thread/3997160
  • https://bugzilla.redhat.com/show_bug.cgi?id=1398698
  • MOS: The system could (more...)

I’m speaking at Advanced Spark Meetup & attending Deep Learning Workshop in San Francisco

In case you are interested in the “New World” and happen to be in Bay Area this week (19 & 21 Jan 2017), there are two interesting events that you might want to attend (I’ll speak at one and attend the other):

Advanced Spark and TensorFlow Meetup

I’m speaking at the advanced Apache Spark meetup and showing different ways for profiling applications with the main focus on CPU efficiency. This is a free Meetup in San Francisco hosted (more...)

Creating a RAC cluster using Ansible (part 2)

In my previous 2 blogposts i explained how to setup a Vagrantfile that deploys 2 virtualbox machines that can be used as a basis for a RAC cluster and how you could use Ansible to deploy RAC on those VM’s. In this post i want to dive a bit deeper into how i setup Ansible and why, keep in mind that this just one way of doing this.

The Github repository containing all the files (more...)

Virtual Development Server: Install Jenkins for Continuos Integration / Delivery / Deployment


For automation of all of my processes I need Jenkins in my development server.

First I had installed Jenkins as Docker container via Vagrant Docker provider. But with this architecture it was very complicated to create docker images and run Docker containers on the Docker host, in this case my Vagrant Virtualbox.

So for simplification I have decided to install Jenkins with the provisioning of the Vagrant Virtualbox via a shell provider in my Vagrantfile:


Problems with big SGAs (>200G) on Linux

I recently had an issue where a database with 240GB SGA (1 huge shared memory segment) configured with hugepages on a system with 512G RAM was suddenly becoming instable and new logons were denied with these error message:

ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
Linux-x86_64 Error: 22: Invalid argument
Additional information: 2667
Additional information: 1736718
Additional information: 215016800256

This was strange because ipcs -a showed all shared memory segments (more...)

OTN Appreciation Day: Oracle Express Edition (XE)

Tim Hall of oracle-base.com fame suggested we should all do an "OTN Appreciation" day in honor of the Oracle Technology Network (OTN), by blogging about our favorite Oracle product or feature.

My personal favorite is Oracle Express Edition (XE), the free version of the world's best relational database.

 Here's what's great about it:

VirtualBox Manual DPK Import Failure: Ran out of Virtual Disk

The DPK scripts are simply amazing. I enjoy the flexibility of the new DPK system. I will confess, creating an HCM demo environment with DPK is not as easy as the prior PUM image method, but it is pretty close. As I prepared for OpenWorld 2016, I thought I would download the latest HCM DPK (update 18) and build out a new demo server on my MacBook. Unfortunately, I wasn't able to use the standard (more...)

Virtual Development Server: Provide Docker images in docker registry for Oracle XE Database and others

For later creation of containers as needed in the deployment process we have first to build docker images whenever we do not find suitable one in docker hub.

For most of my development I need a oracle database. On the internet you can find a lot of Dockerfile’s for this, but no ready image. This is because for running a database you have to accept a license and this happens when you download the installation (more...)

Building “Ready to Deploy” Oracle VM Templates

I’ve been playing a bit lately with Oracle VM on a few different platforms (ODA, Exalytics, Private Cloud Appliance) and was tasked with creating a good Oracle VM template image for Oracle Linux 7. Oracle makes templates available on eDelivery (https://edelivery.oracle.com) that present you with VM configuration questions on first boot, but those VM templates have a few limitations that make them hard to use:

  1. The templates have a minimal Linux installation, and are (more...)

Virtual Development Server: Add swapfile to VirtualBox as requirement for installing Oracle or build Oracle docker images

As I want later build Oracle docker images, some of this need a swapfile.

Per default my used Vagrantbox, does not have one, so later steps will fail.

As in the last blog I use a Vagrant shell provider.

  # add swapfile to the box
  config.vm.provision :shell, :path => "add_swap.sh"

This calls the script add_swap.sh in the created VirtualBox machine.
Make sure, that you create your swapfile on a supported (more...)

Redirecting ILOM Console Via SSH Tunneling With Putty

While preparing for a virtualized Exalytics upgrade, I was testing the various connection methods that would be needed.  Last on the list was to validate that I could connect to the ILOM’s web interface, launch the java console, and mount an ISO file from my laptop to the machine.   This is necessary because the Oracle VM server upgrade for a virtualized Exalytics requires you to boot from a specific ISO file in order to patch (more...)