Data Visualization Desktop Data Flow Component

My previous post contained a brief description of Data Visualization Desktop (DVD) new features in, in terms of sources, visualisations and components. In this post we're going to simulate a typical analyst use case and understand how DVD can support the process.

Data Visualisation Desktop is a tool aimed at departmental analysis, with data coming from different sources and results that need to be delivered quickly. Given the ad-hoc nature of (more...)

Conjuctive Normal Form

I recently tweeted about a comment I’d picked up at the Trivadis performance days regarding tablescans and performance.

“If you can write your SQL in conjunctive normal form it can help the optimizer to offload more predicates”

Inevitably someone asked me if I had an example to demonstrate this – I didn’t, and still don’t really, but here’s an interesting demo based on an example from the Oracle In-Memory blog showing how the optimizer will (more...)

Oracle EMPTY_CLOB Function with Examples

In this article, I’ll explain what the EMPTY_CLOB function does and show you an example of how to use it. Purpose of the Oracle EMPTY_CLOB Function The EMPTY_CLOB function is used to initalise a CLOB column to EMPTY. It can be used in several places: In an INSERT statement In an UPDATE statement Initialising a […]

AWR Summary Data Extracts

A long time ago (in a galaxy far away) I wrote a series of blog posts about directly extracting useful sets of data from the AWR snapshots in the DBA_HIST tables for subsequent analysis and graphing using things like Excel. This post is to summarise where I got to on this, and provide links back to the main posts for future reference.

A guiding principle of my approach was that I wanted to avoid the (more...)

Congratulations to Certus – Thank you to everyone who Voted

Back in August I asked for your vote in The UKOUG Partner Awards. I always say how important these are because they are voted for by end users.

It is a hard process for me, I am not allowed to do anything for PYA by UKOUG because I am a partner and there has to be a total separation. Most people understand that but my boss rang me 3 times on the day asking (more...)

Real Time Ambient Display at OpenWorld: The Software (for the Hardware)

This is part 2 of my blog post series about the Ambient Visualization hardware (part 1).  Also, please read John’s post on details about the creation of the actual visualization, from concept to build.  In the first part, I focused on the hardware, a sonar sensor connected to a NodeMCU.  In this second part, the focal point will be the software.

When I started working with ESPs a few years ago I was all (more...)

Create a Python Module

Sometime formal programming documentation is less than clear. At least, it’s less than clear until you’ve written your first solution. The Modules section of the Python language is one of those that takes a few moments to digest.

Chapters 22 and 23 in Learning Python gives some additional details but not a clear step-by-step approach to implementing Python modules. This post is designed to present the steps to write, import, and call a Python module. (more...)

Taking a peek at SYS_CONTEXT

There was Twitter discussion about using context variables, accessed via SYS_CONTEXT within queries. It’s an easy means of passing parameters into a view. The question that got asked was – does a sys_context variable act exactly like a bind variable. Let’s take a look at a simple demo to explore that.

We’ll create a table with 1 row with a value of ‘a’, and 100,000 rows with a value of ‘b’. We’ll index that column, (more...)

Python for loops

It’s always interesting to explain a new programming language to students. Python does presents some challenges to that learning process. I think for loop can be a bit of a challenge until you understand them. Many students are most familiar with the traditional for loop like Java:

for (i = 0; i < 5; i++) { ... }

Python supports three types of for loops – a range for loop, a (more...)

Translating SQL (a migration tool)

When you are moving from another database to Oracle, in a perfect world, you’d set aside plenty of time to refactor all of your code and re-engineer your applications to get the maximum benefit out of the new database technology.  But there are not many “perfect worlds” out there  in the IT landscape Smile  So sometimes we have to “make do” with the time and budget constraints that are placed upon us.  To (more...)

Quickly built new Python graph SQL execution by plan


I created a new graph in my PythonDBAGraphs to show how a plan change affected execution time. The legend in the upper left is plan hash value numbers. Normally I run the equivalent as a sqlplus script and just look for plans with higher execution times. I used it today for the SQL statement with SQL_ID c6m8w0rxsa92v. It has been running slow since 10/11/2016.

Since I just split up my Python graphs into multiple smaller scripts (more...)

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...)

Oracle Forms & Reports available

Since a few hours the latest Release of the Oracle Forms & Reports is available for download in Oracle Technology Network under

The related documentation can be found under

For all the lovers of Oracle Reports, here is the bad news: It's time to prepare for bye-bye !

The next planned Oracle Reports will be the terminal release for Oracle Reports !

Note can be found here

Weblogic available

Since a few hours the latest Release of the Oracle WebLogic Server is available with Oracle Technology Network for download.

The Installation sources can be found under:

The documentation for the latest Oracle WebLogic Server can be found under

Oracle Discoverer Security Alert – High impact to SOX Compliance and Financial Reporting

For those clients using Oracle Discoverer, especially those using Discoverer with the Oracle E-Business Suite for financial reporting, the October 2016 Oracle Critical Patch Update (CPU) include a high-risk vulnerability reported by Integrigy Corporation. CVE-2016-5495 is a vulnerability with the Discoverer EUL Code and Schema and has a base score 7.5. Integrigy believes this vulnerability affects all versions of Discoverer used with the Oracle E-Business Suite and that the confidentiality, integrity, and availability of (more...)

Tim Gorman at AZORA meeting tomorrow in Scottsdale

VirtualBox 5.1.8

VirtualBox 5.1.8 has burst through the chest of it’s host organism.

Downloads and changelog are in the usual places. It’s a maintenance release, so there are a bunch of bug fixes in there.

I’ve installed it on macOS (Sierra), Windows 7 and Oracle Linux 6 with no problems.SO far no dramas. 🙂

Happy upgrading!



VirtualBox 5.1.8 was first posted on October 19, 2016 at 2:19 pm.
©2012 "The (more...)

All Flash Arrays: Active/Active versus Active/Passive


I want you to imagine that you are about to run a race. You have your trainers on, your pre-race warm up is complete and you are at the start line. You look to your right… and see the guy next to you, the one with the bright orange trainers, is hopping up and down on one leg. He does have two legs – the other one is held up in the air – he’s just choosing to (more...)

Data Visualization Desktop

Yesterday Data Visualization Desktop (DVD) Version was released. DVD, since its first release, aims to extend Oracle's Data Visualization portfolio by adding a desktop tool allowing data visualization capabilities directly to end users without the intervention of the IT department, in line with the Gartner's bi-modal IT.

The new version adds several capabilities to the existing product like visualization types, data sources and a wrangling option. This post will share the (more...)

Oracle Critical Patch Update for October 2016

The Critical Patch Update for October 2016 was released on October 18th, 2016. Oracle strongly recommends applying the patches as soon as possible. 

Visit the URL below for more updates