Padraig O'Sullivan

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Updated: 17 hours 58 min ago

Blogging at Now

Tue, 2009-02-24 22:59
I've decided to start blogging with WordPress now as it just makes putting code samples and things like that so much easier! Also, I had a domain name for a while so I figured I might as well use it and it will encourage me to blog more. I really want to blog more at the moment since I'm working on an interesting project for my database course this semester.You can find my blog here from now on. Padraig

Drizzle: A Pretty Cool Project

Wed, 2009-01-28 20:38
Drizzle is a pretty cool project whose progress I've started following in the last few weeks. I'm trying to contribute in a tiny way if I can by confirming bug reports. If I had more time, I'd like to try resolving some bugs. Hopefully, I'll find some spare time to do that in the future.I think its definitely a project worth keeping an eye on though. Check it out if you have the time.Padraig

A Subtle Bug

Sat, 2009-01-24 21:35
At university, I work in a research group where we are developing an application in C++ that runs on both Linux and Windows. Since I do most of my development on Linux, I rarely test our application on Windows (other people in the group who run Windows test on that platform). Recently, one of my colleagues was encountering a problem while running our application on Windows that I was not Padraig

What is Direct Data Placement

Tue, 2009-01-06 01:02
I'm currently studying Oracle's white paper on Exadata and came across the following paragraph:"Further, Orace's interconnect protocol uses direct data placement (DMA - direct memory access) to ensure very low CPU overhead by directly moving data from the wire to database buffers with no extra data copies being made."This got me wondering what direct data placement is. First off, the interconnectPadraig

Semester Project Finally Finished

Tue, 2008-12-16 09:15
We just finished our semester project yesterday for the class I am taking on High Performance Computing. It was a pretty interesting project based on the topic of software fault injection.More details can be found in the project report here.Padraig

Its Been a While

Sun, 2008-11-30 18:46
I had removed this blog but kept getting some emails asking for links to certain posts so I just posted some old posts again so that they are available to anyone who is interested in them.As an update for what I'm doing, I'm currently in my second year of graduate school. I plan on taking a grad class in database systems next semester so that should be interesting. I'll get to learn a lot about Padraig

Configuring Oracle as a Service in SMF

Sun, 2008-11-30 15:33
In Solaris 10, Sun introduced the Service Management Facility (SMF) to simplify management of system services. It is a component of the so called Predictive Self Healing technology available in Solaris 10. The other component is the Fault Management Architecture.In this post, I will demonstrate how to configure an Oracle database and listener as services managed by SMF. This entails that Oracle Padraig

Building a Modified cp Binary on Solaris 10

Sat, 2008-11-29 21:48
I thought I would write a post on how I setup my Solaris 10 system to build an improved version of the stock cp(1) utility that comes with Solaris 10 in case anyone arrives here from Kevin Closson's blog. If you are looking for more background information on why I am performing this modification, have a look at this post by Kevin Closson.GNU Core UtilitiesWe need to download the source code for Padraig

srvctl Error in Solaris 10 RAC Environment

Sat, 2008-11-29 21:48
If you install a RAC environment on Solaris 10 and set kernel parameters using resource control projects (which is the recommended method in Solaris 10), then you will likely encounter issues when trying to start the cluster database or an individual instance using the srvctl utility. As an example, this is likely what you will encounter:$ srvctl start instance -d orclrac -i orclrac2PRKP-1001 : Padraig

Oracle 10gR2 RAC with Solaris 10 and NFS

Sat, 2008-11-29 21:46
Recently, I setup a 2 node RAC environment for testing using Solaris 10 and NFS. This environment consisted of 2 RAC nodes running Solaris 10 and a Solaris 10 server which served as my NFS filer.I thought it might prove useful to create a post on how this is achieved as I found it to be a relatively quick way to setup a cheap test RAC environment. Obviously, this setup is not supported by Oracle Padraig

Creating a UFS File System on an External Hard Drive with Solaris 10

Sat, 2008-11-29 21:45
Recently, I wanted to create a UFS file system on a Maxtor OneTouch II external hard drive I have. I wanted to use the external hard drive for storing some large files and I was going to use the drive exclusively with one of my Solaris systems. Now, I didn't find much information on the web about how to perform this with Solaris (maybe I wasn't searching very well or something) so I thought I Padraig

Observing Oracle I/O Access Patterns with DTrace

Tue, 2008-11-25 16:35
In this post, I will use the seeks.d and iopattern DTrace scripts, which are available as part of the DTraceToolKit (This toolkit is an extremely useful collection of scripts created by Brendan Gregg), to view the I/O access patterns typical of Oracle. DTrace is able to capture data throughout the kernel and so the job of finding access patterns has been greatly simplified.The system on which Padraig

Playing with Swingbench

Tue, 2008-11-25 16:35
Swingbench is a free load generator (and benchmarks generator) designed by Dominic Giles to stress test an Oracle database. In this post, I will be playing with Swingbench and showing how it can be used. This article will focus on comparing the performance of buffered I/O versus un-buffered I/O (i.e. direct I/O) using the Swingbench tool. Since this article is not about direct I/O (I encourage Padraig

Generating a System State Dump on HP-UX with gdb

Tue, 2008-11-25 16:34
I have previously used the gdb (GNU Debugger) to generate oracle system state dumps on Linux systems by attaching to an Oracle process. The ability to do this has been well documented by Oracle on Metalink (Note 121779.1) and in other locations.The problem with this is that it does not work on the HP-UX platform. I found this out at the wrong time when trying to generate a system state dump Padraig

Installing & Configuring a USB NIC on Solaris

Tue, 2008-11-25 16:34
In this post, I will provide a very quick overview of how to install and configure a USB network interface on Solaris.Obtaining the USB DriverThe driver for a generic USB network interface which should cover the majority of USB NIC devices can be downloaded from here.Installing the USB DriverAfter downloading the driver, uncompress the gunzipped file and extract the archive as the root user. # Padraig

Temporary Tablespace Groups

Tue, 2008-11-25 16:33
Temporary tablespace groups are a new feature introduced in Oracle10g. A temporary tablespace group is a list of tablespaces and is implicitly created when the first temporary tablespace is created. Its members can only be temporary tablespaces.You can specify a tablespace group name wherever a tablespace name would appear when you assign a default temporary tablespace for the database or a Padraig

OCFS2 Mount by Label Support

Tue, 2008-11-25 16:32
While messing around with OCFS2 on my RHEL4 install, I discovered that if I created an OCFS2 filesystem with a label, I was unable to mount it by that label. I would encounter the following:# mount -L "oradata" /ocfs2mount: no such partition found#I found this quite strange and did some investigation. The version of util-linux that was present on my system after a fresh RHEL 4 install was - Padraig

Installing a Back Door in Oracle 9i

Tue, 2008-11-25 16:32
In this post, we will demonstrate a way an attacker could install a back door in a 9i Oracle database. The information on this post is based on information obtained from Pete Finnigin's website and the 2600 magazine. The version of the database we are using in this post is:sys@ORA9R2> select * from v$version;BANNER----------------------------------------------------------------Oracle9i EnterprisePadraig

White Paper at Oracle OpenWorld

Tue, 2008-11-25 16:31
A white paper that I was part of writing is being presented at Oracle OpenWorld this week. The paper is entitled 'High Availability Options for the Oracle Database'. It is being presented by Dan Norris and I wrote the sections on Export/Import and data pump. The paper is available for download from the IT Convergence website here.Dan is kinda like my mentor here at IT Convergence. He has a lot ofPadraig

First Paper Accepted

Tue, 2008-11-25 16:29
I just found out that my first paper has been accepted! Its a pretty nice feeling. This paper was based on research I did in the summer of 2005 with the MISL research group in UCC.A pre-print version of the paper is available here. It was accepted to a conference called First International Workshop on Practical Issues in Building Sensor Network Applications.Now I'm hoping my paper on small-world Padraig