Preventing a SPOF with CMAN 12c

I have already written about the use of Connection Manager 11.2 to govern access to a database. While researching this piece I have updated the original post so that it’s relevant for 12c as well.

Although the idea of using Connection Manager is tempting, the obvious first question is about high availability of the process. After all, if the gatekeeper to your database environment fails, you are effectively closed for business. One option would (more...)

Investigating kernel dives using ftrace.

This blogpost is about using the linux ftrace kernel facility. If you are familiar with ftrace and specifically the function_graph tracer, you might already be aware of this functionality. This is Linux specific, and this facility is at least available in kernel 2.6.39 (Oracle’s UEK2 kernel).

What is a ‘kernel dive’? Whenever a process is running, it should mostly be in ‘user mode’, executing the program it is supposed to run. However, during (more...)

Training Thursdays: Firewall Services in Oracle Linux Training

The default firewall service in Oracle Linux 7 is firewalld. In previous versions of Linux, you use iptables. firewalld offers several advantages over iptables:
  • Changes do not require restart of the firewalld service.
  • Networks can be separated into different zones based on the level of trust.

Firewall services is one of the many topics covered in Oracle's Linux system administration training. You can learn about firewalld and many other topics by taking the Oracle Linux (more...)

System Metrics Collectors

The need to monitor and control the system performances is not new. What is new is the trend of clever, lightweight, easy to setup, open source metric collectors in the market, along with timeseries databases to store these metrics, and user friendly front ends through which to display and analyse the data.

In this post I will compare Telegraf, Collectl and Topbeat as lightweight metric collectors. All of them do a great job of collecting variety (more...)

GoldenGate and Netwworking

I have never delved into networking for GoldenGate since things just work. Due to security tightening, telnet is no longer available to verify opened port.

What’s to follow is a demo for ports being listened by GoldenGate when manager started and ports listened and when PUMP Extract is started as part using DYNAMICPORTLIST.

Also, how to test opened port using (nc – arbitrary TCP and UDP connections and listens)

Both source and target are running on the (more...)

FRIDAY SPOTLIGHT: New VirtualBox 5.1 and Private Cloud Appliance Refresh

This week had been a busy one for us. We had several exciting announcements that we would like to inform you about.

Oracle VM VirtualBox 5.1

To enable organizations and developers to more easily and flexibly create and deploy on premises and cloud applications, we are pleased to announce the general availability of Oracle VM VirtualBox 5.1, the latest release of the world’s most popular free and open source, cross-platform virtualization software. The (more...)

Tales from the field: potential reasons for PDB plug-in violations part 2

In the first part of this little series I explained how a missing (default) tablespace in a PDB can have an impact when opening it. In this instalment I’ll add another common cause for PDBs not opening in read-write mode: different patch levels between the PDB to be plugged in and the CDB.


Assume for a moment that you upgraded Oracle binaries from to (more...)

Visit us and Attend Oracle and Tegile Session at Cisco Live!

This year Oracle will be presenting at Cisco Live 2016,  July 10th – 14th,  Mandalay Bay Convention Center, Las Vegas in Tegile's theatre and we will have an Oracle engineer at the booth answering your questions about how we work together. Oracle and Tegile had been collaborating and had been involved in joint engineering engagements last 3 years:

  • Tegile is part of the Oracle Hardware Certification (HCL) Program
  • Hardware certified and supported on latest Oracle VM (more...)

Oracle Linux 7 – What’s New Training from Oracle University

Oracle Linux 7: What's New for Administrators Ed 1 explores the expanded possibilities Oracle Linux 7 brings system administration. Utilize new and modified tools, task flows, and options within installation, networking, management, storage and more.

This course addresses system administration topics that are different in Oracle Linux 7 than they are in previous versions of Oracle Linux.

You'll develop an understanding of how the boot process (more...)

Manually downloading Java For Use With Webupd8’s apt-get Package

Oracle Java is one of the biggest problems in life. That’s just a fact. Half of it is the fact that you have to download it directly from Oracle each time, quarter of it is the almost daily updates (compounded by the first problem), and the remainder is dealing with the fact that the first problem

FRIDAY SPOTLIGHT: Code Faster, More Securely with the Oracle Developer Studio

We are excited this Friday to talk about the latest Oracle Developer Studio 12.5  announced last week with breakthrough features for developer efficiency!

Optimized to complement Oracle’s complete hardware and software stack, Oracle Developer Studio helps companies build higher quality code, in less time.

Oracle Developer Studio 12.5 delivers optimized compilers, advanced analysis tools and a multi-language aware IDE for easy development of fast, reliable and highly secure applications for Oracle Solaris and (more...)

Friday Spotlight: Re-cap of RedHat Summit 2016

This Friday we want to give you a quick snapshot from Red Hat Summit where Oracle was one of the silver sponsors.  At our booth, we have showcased Oracle Linux, OpenStack, Oracle VM, VirtualBox, Private Cloud Appliance and Software Defined Networking products. Our engineers and experts talked about the building blocks needed for Cloud; Linux, OpenStack, Engineered Systems and virtualization solutions from Oracle. 

Our session was about "Implementing Platform Security for Cloud Computing" where (more...)

Oracle Linux, OpenStack & Docker Partner Update Webinar – July 1

Join us for the Oracle Linux, OpenStack & Docker Partner Update Webinar where you will:

  •     Learn how to increase performance and build Private Clouds.
  •     Learn how to deliver maximum performance and security
  •     Discover Modern Application development with Docker
  •     Get the latest OpenStack overview
  •     Learn how to access partner sales and technical boot-camps

Date:  July 01, 2016

Time: 10:00 AM - 11:00 AM (GMT) Casablanca, Monrovia, Reykjavik

In order to register, (more...)

Tales from the field: potential reasons for PDB plug-in violations part 1

Container Databases have been an area that I have researched intensively over the past years. With this post (and hopefully some others that follow) I would like to demonstrate some of the new situations the DBA might be confronted with. Please don’t use this post to give the new 12c architecture a hard time: standardised deployments (which I love) help you a lot. Not only do your DBA scripts work reliably everywhere, but the error condition (more...)

Install DataStax Cassandra 3 on Debain/ Ubuntu

The following process will install the DataStax distribution of Cassandra on any Debian based system, such as Debian or Ubuntu. We’ll use the official DataStax apt repositories to install Cassandra using apt-get. Cassandra is written in Java and the latest version (at the time of writing) of Cassandra requires Java 8. You can use either OpenJDK or

Developer Days VM Startup and Shutdown, SQLcl

| Jun 16, 2016
If you're developing on a remote platform, chances are that you are using a Virtual Machine. (VM)  In Oracle, we release a virtual machine called the  "Oracle Developer Days".    This is available on the Oracle Technology Network and ala google.  Todays hack is setting up headless vm's, ports and aliases to speed up your day. (This post took a lot longer to write that the aliases we set up!)

For this (more...)

Little things worth knowing: auto-DOP or hint-which one takes precedence?

This is just another short post about one of the little things worth knowing. Assume you are on for example and you want to know if parallel_degree_limit reliably keeps the degree of parallelism at bay, for all sessions and queries across the board. After all, every machine has finite CPU (and other) resources that shouldn’t be exhausted. Setting parallel_degree_limit of course only has an effect if you set parallel_degree_policy to limited, auto (more...)

Can’t Display 256 Colors

If you’re reading this post, you most likely are trying to run the Oracle Database 11g or 12c runInstaller program, and it’s failing a critical dependency check and displaying an error like the one below. If so, choose n because if you choose y it won’t launch the Oracle Installer.

Starting Oracle Universal Installer...
Checking Temp space: must be greater than 500 MB.   Actual 30824 MB    Passed
Checking swap space: must be greater than  (more...)

The Oracle database, in-memory parallel execution and NUMA

In a previous article called ‘memory allocation on startup’ I touched on the subject of NUMA; Non Uniform Memory Access. This article is about how to configure NUMA, how to look into NUMA usage and a real life case of NUMA optimisation using in-memory parallel execution.

At this point in time (start of the summer of 2016) we see that the CPU speed competition has stagnated and settled at somewhere below maximally 4 gigahertz, and (more...)

Linux BPF/bcc for Oracle Tracing

Topic: In this post you will find a short discussion and pointers to the code of a few sample scripts that I have written using Linux BPF/bcc and uprobes for Oracle tracing.

Previous work and motivations

Tools for dynamic tracing are very useful for troubleshooting and internals investigations of Oracle workloads. Dynamic tracing probes on the OS/kernel, can be used to measure the details for I/O latency for example. Moreover probes on the Oracle (more...)