Integrating SVN into Eclipse

Being a CVS Version Control Person, I’ve had to learn Subversion as part of Open Source Contribution. Both MySQL and JMeter use SVN.

Steps for integration of SVN into Eclipse IDE. Refer to Subclipse for more information.

Installation of JMeter via SVN

  • Start Eclipse
  • Help | Software Updates | Find and Install
  • Search For New Features To Install [Next]
  • [New Remote Site]
  • URL:
  • [Finish]
  • Tick Subclipse [Next]
  • I accept Terms and Condtions [Next]
  • Finish


  • Restart Eclipse
  • Window | Open Perspective | Other | SVN Repository Exploring
  • Right Click New | Repository Location
  • URL [Finish]
  • Right Click on Node, Checkout
  • Check out as project in Workspace [Finish]

Installing MySQL 5 via rpm

I don’t think I’ve ever installed MySQL via .rpm I have always installed via .tar.gz primarilarly because I’m an /opt system administrator from my old UNIX days. so my first experience installing on my CentOS 4.2 (aka RHEL 4).

$ rpm -Uvh MySQL-server-standard-5.0.19-0.rhel4.i386.rpm
warning: MySQL-server-standard-5.0.19-0.rhel4.i386.rpm: V3 DSA signature: NOKEY, key ID 5072e1f5
error: Failed dependencies:
perl(DBI) is needed by MySQL-server-standard-5.0.19-0.rhel4.i386
Suggested resolutions:
$ rpm --import /usr/share/doc/centos-release-4/RPM-GPG-KEY
$ yum install perl-DBI-1.40-8
$ rpm -Uvh MySQL-server-standard-5.0.19-0.rhel4.i386.rpm
warning: MySQL-server-standard-5.0.19-0.rhel4.i386.rpm: V3 DSA signature: NOKEY, key ID 5072e1f5
Preparing... ########################################### [100%]
1:MySQL-server-standard ########################################### [100%]
To do so, start the server, then issue the following commands:
/usr/bin/mysqladmin -u root password 'new-password'
/usr/bin/mysqladmin -u root -h lamda.arabx password 'new-password'
See the manual for more instructions.
Please report any problems with the /usr/bin/mysqlbug script!
The latest information about MySQL is available on the web at

Support MySQL by buying support/licenses at
Starting MySQL...................................[FAILED]

Failed!!! What the!!!!

So turn to my good friend Morgan for help. I'd already done a little google research, but it took Morgan about 15 secs to know the problem, and know he had already experienced this with other clients.

Some References:

Some Analysis:

$ system-config-securitylevel
# shows that I have SELinux enabled.
$ /usr/sbin/selinuxenabled && echo "yes"
$ restorecon -R -v /var/lib

Ok, its working now. But wait there is no mysql command? Again, I'm .tar.gz user, had to realise the client is a seperate RPM.

rpm -ivh MySQL-client-standard-5.0.19-0.rhel4.i386.rpm

Well my first .rpm experience was, well eventful none the same.

More on Oracle Procedures Functionality (Part 2)

As mentioned in my earlier post Emulating Oracle Output Functionality, I’ll be speaking at the MySQL Users Conference on the topic of MySQL for Oracle Developers. Here is the second in a series of points regarding current MySQL Stored Procedures and Functions functionality.

  • 3. Named Parameters
  • 4. Procedure Overloading

3. Named Parameters

Parameters passed to Procedures under normal operations can be considered positional parameters. For each parameter, a calling statement is required to pass the same number of parameters and in the same order. Named parameters allows the user to pass parmeters in the order of their choosing, and also not pass all parameters.

For Example, consider the following Oracle Stored Procedure definition.

                    dte IN DATE DEFAULT SYSDATE,
                    str IN VARCHAR2 DEFAULT NULL,
                    str2 IN VARCHAR2 DEFAULT NULL);

This can be called in several ways, here are few examples.

  EXAMPLE_PROCEDURE(9,  '01-MAR-2006', 'Hello World', NULL);
  EXAMPLE_PROCEDURE(dte => '01-MAR-2006');
  EXAMPLE_PROCEDURE(dte => '01-MAR-2006', str2 => 'Hello World');

The key to being able to use named parameters, is the addition of the DEFAULT syntax in the variable definition.

Giuseppe Maxia has many MySQL stored procedures, and I applaud his initiate with The MySQL General Purpose Stored Routines Library. Included here is an implementation of handling named parameters. I can’t say I’ve used it personally, however I did browse the code (another Open Source benefit).

4. Procedure Overloading

Oracle provides the capability like Java, which allows for multiple procedures to have the same name, but have a different set of parameter arguments.

Oracle provides the ability to overload a Procedure call with the same number of arguments and varying datatypes, for example, going with the earlier DBMS_OUTPUT.PUT_LINE analogy, Oracle has the following specification.


Likewise, it possible to have procedures with different numbers and types of arguments.



As MySQL growth continues and developers take up placing greater business logic in the database with Stored Procedures, there may be merit to consider these points. On the flip side, 10 years ago, business logic was placed in the database for many reasons including the extent of capable client programming languages, a Client/Server architecture and of course tight coupling with Oracles GUI products. One could argue a justification as to how much business logic is stored in the database, and how much is managed within an application. Given the advent of the Web, and multiple applications and clients assessing coporate data, it’s logical to place essential logic as close to the source of the data as possible, and the introduction of Stored Procedures in MySQL 5 released last year provided the capacity to consider this.

At this time, I would err on the conservative side with the use of Stored Procedures. The type of application, requirements and signficantly the age of the product (being a new product or existing legacy product) all affect the outcome. As mentioned, Giuseppe feels strongly regarding named parameters, and has provided a workaround. The benefit with Open Source is this FREEDOM clearly exists when the community contributes. This can only benefit MySQL in areas such as Stored Procedures.

Myself, only a few days ago over the weekend, I took an Java Open Source product, that lacked the capacity to support the calling of Stored Procedures via JDBC, developed it myself and then submitted my work back to the Apache community. I was even more happy when it was accepted unaltered, committed and in the nightly build for the next day. Read More. I’m now working on the next contribution to the same project, providing JDBC Transaction Support. While this may seem a sidetrack, I’m actually specifically using this product in testing and usability of MySQL, so ultimately everybody wins.

Correction to earlier MySQL Statement

I stand corrected on my earlier post Emulating Oracle Output Functionality (which I’ve updated) when I made a reference to MySQL catching up. That was not what I was implying, that MySQL had to catchup to Oracle. I was indeed making reference that MySQL is a 10 year old product, Oracle almost 30, and with a far greater historical R&D budget, MySQL as an organisation has for lack of a better term, entered the race at a later time. One could also argue it’s not a race, I’m just using this analogy.

For those that might have thought this in reading my earlier article, I’d encourage you to re-read my updated introduction for my clarification and correction.

The comment was made to me, “Oracle is very good at being Oracle” which is totally correct, and the “MySQL’s market now overlaps that of Oracle, and so there is competition.” Indeed Oracle, as a leader in the RDBMS industry has directed development in functionality and features.

We (being the MySQL product and Open Source) are indeed in competition (with other RDBMS products, both commercial and open source) , and will always be, however those that know me would also know that differing products serve to provide differing features and functionality in enterprise solutions. Some have strengths over others, and also weaknesses.

I am a strong advocate of larger enterprises currently using Oracle to embrace both Oracle and MySQL within an organisation for the benefit of serving differing purposes. I do not believe they are mutually exclusive. I believe there needs to be a looser coupling in the emerging marketplace. Of course, if a new company was starting tomorrow, and wanted to use Oracle, I would question the requirements as MySQL will serve the needs for most practical enterprise solutions. Had that question been asked 5 years ago, it would depend signficantly on the requirements, 10 years ago it would not have been a consideration.

A Basic MySQL Developer Installation

Given a new Linux Installation, the following is my recommendation for installation of MySQL for a experienced software developer giving flexibility in a development environment.

1. Under normal circumstances, most distros include MySQL either in a default server installation or on the distribution CD’s. You should first ensure MySQL is not installed.

2. All products can be downloaded from the MySQL Downloads page.

3. Download MySQL 5.1 Beta – Linux (non RPM, Intel C/C++ compiled, glibc-2.3), this product is close to production release and stable. This also includes both Server and Client as well as provides flexibility in installation location and multiple installations.

3. Download MySQL Administrator 1.1.6.

4. Download MySQL Query Browser 1.1.18.

5. Download MySQL 5.1 Manual


su -
groupadd mysql
useradd -g mysql mysql
cd /opt
tar xvfz mysql-5.1.7-beta-linux-i686-icc-glibc23.tar.gz
ln -s mysql-5.1.7-beta-linux-i686-icc-glibc23 mysql
tar xvfz mysql-administrator-1.1.6-linux-i386.tar.gz
tar xvfz mysql-query-browser-1.1.18-linux-i386.tar.gz
tar xvfz refman-5.1-en.html-chapter.tar.gz
mv html-chapter mysql-manual-5.1
cd mysql
echo "[mysqld]
port=3306" > my.cnf
cd /opt
chown -R root /opt/mysql
chown -R mysql /opt/mysql/data
chgrp -R mysql /opt/mysql
chown -R root /opt/mysql/bin
cd /opt/mysql
./bin/mysqld_safe &
./bin/mysqladmin -u root password 'new-password'
./bin/mysqladmin -u root -h `hostname` -pnew-password password 'new-password'
./bin/mysqladmin -pnew-password shutdown
echo "PATH=/opt/mysql/bin:/opt/mysql-administrator/bin:/opt/mysql-query-browser/bin:$PATH; export PATH" > /etc/profile.d/
. /etc/profile.d/   # Just for this session
cp support-files/mysql.server /etc/rc.d/init.d
chkconfig mysql.server on


The MySQL server will start automatically on System boot

To run the MySQL Client

mysql -uroot -pnew-password mysql

To run the MySQL Administrator


To run the MySQL Query Browser


Now that I remember all this, perhaps RPM’s are the way to go, I just don’t like the structure in deployed files.

What should I install?

I was asked a simple question today by a collegue who is an experiened Java Developer and Oracle user and had just installed SUSE on his personal laptop, to align closer with his work environment. What MySQL should I install, the MySQL web site has this and this and this?

Simple question, but the answer isn’t as simple, especially when MySQL now has a number of different products encompassing client functionality in addition to the MySQL server.

Oracle got it right with the latest edition Oracle 10g Express Edition (XE). A simple one rpm install that includes the Oracle Server, Oracle client, a Web Based Administrator, Query Tool and Application Development tool. I guess as we are all experienced, the simple question isn’t something we have a some notes on handy, hence the purpose of my entry A Basic MySQL Developer Installation. NOTE: This is for a developer environment, installation would be simplier using RPM’s for a compatible Distro.

On that note, It would be good for MySQL to provide a more complete installation of it’s suite of products rather then letting 3rd parties package it all together. Problem is there are so many possible combinations, what do you do.

Data Modelling

I’m a data modeller. I specialise in this, and for a number of years on large projects I’ve been able to focus on this single task within the System Development Life Cycle of software development for several months at a time. Unfortunately what depresses me the most, is I can’t get a full time position in what I’m an expert in. It’s not a specialised skill that an organisation can use on a full-time basis, unless it’s a large organisation, and quite frankly, Brisbane isn’t a market that can support the diversity of large organisations. (caveat, large organisations that are proactive in software development, not just large organisations that have significant IT requirements, but do not work proactively). This is why I can also do Software Development, Database Administration, and even System Administration. Again, I’m not good enough to fill one of these positions in a larger organisation as an expert, but I can generally hold my own, usually even with surpising results. (Side note, even this week, I was providing a possible solution and tool for system adminstration across a large organisation, and it was 5 mins work. Something the paid full-time system administrators were not providing????)

I only started looking at Domas Mituzas wordpress: friendly look at query log. I didn’t have to read far to see where it was going, and well I quite quickly turned off, sorry Domas, I’m sure your concluding points were valid. This is my point, and it has been echoed in our local MySQL users group as well, the lack of appropiate database design in open source projects. There are several contributors, but one I put down to the “Hobbist and the Professional Syndrome”. A topic for further discussion, but in summary here are the bullet points from a slide in a presentation I prepared.


  • Downloadable software and examples
  • Online tutorials
  • Books like Learn in 24 hours/For Dummies


  • Formal Qualifications
  • Grounding in sound programming practices
  • Understanding of SDLC principles
  • Worked in team environment

Middle Ground Developer

  • Time to skill verses output productivity
  • Depends on environment and requirements

And on a final note, I guess why doing some raving. I find it criminal that organisations encourage at times a level of incompetence by promoting people that develop bad code into positions where they can continue to ensure that bad code stays, and further business decisions only engrain an organisation down the continued wrong path. There is already enough poor software developers out there that give the industry a bad name, but the good ones are few and far between.

What do we do, how can we solve this problem? I don’t think it can be solved now in the Open Source community. Adopting an Agile Development methodology such as Extreme Programming (XP) for example, it a very good start in organisations, something I’ve been working with now, or working with the principles for 6 years.

PS: Modelling is actually spelt both Modeling and Modelling (2 l’s) across the various English derivitives. Just incase somebody wanted to make comment.

Format new Linux Disk

fdisk /dev/hdb
mkfs.ext3 /dev/hdb1
mkdir /u03
mount -t ext3 /dev/hdb1 /u03
ls /u03
umount /u03
vi /etc/fstab
mount /u03

Contributing to JMeter

As part of my using JMeter for the purpose of testing a new Transactional storage engine PBXT for MySQL, I’ve been investigating the best approach for handling transactions. Read more about earlier decisions at my earlier post Testing a new MySQL Transactional Storage Engine.

I found that the JMeter JDBC Sampler only supports SELECT and UPDATE Statements, and not calls to stored procedures. This is just one approach I’m considering taking.

Well, I guess it’s time to contribute code to an Apache Project. I’ve modified code and logged bugs before for Tomcat, but this will be my first attempt of modify code and submit.

A summary of what I did (really for my own short term memory):

Now I just have to wait to see if it’s accepted. Regardless, it works for me. And that’s Open Source. FREEDOM

svn checkout jmeter

$ svn diff >
$ cat
---    (revision 388876)
+++    (working copy)
@@ -23,6 +23,7 @@
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.sql.CallableStatement;

 import org.apache.avalon.excalibur.datasource.DataSourceComponent;
 import org.apache.jmeter.samplers.Entry;
@@ -45,6 +46,8 @@

        public static final String QUERY = "query";
        public static final String SELECT = "Select Statement";
+       public static final String UPDATE = "Update Statement";
+       public static final String STATEMENT = "Call Statement";

        public String query = "";

@@ -69,6 +72,7 @@
                log.debug("DataSourceComponent: " + pool);
                Connection conn = null;
                Statement stmt = null;
+               CallableStatement cs = null;

                try {

@@ -88,14 +92,19 @@
                                        Data data = getDataFromResultSet(rs);
                                } finally {
-                                       if (rs != null) {
-                                               try {
-                                                       rs.close();
-                                               } catch (SQLException exc) {
-                                                       log.warn("Error closing ResultSet", exc);
-                                               }
-                                       }
+                                       close(rs);
+                       // execute stored procedure
+                       } else if (STATEMENT.equals(getQueryType())) {
+                               try {
+                                       cs = conn.prepareCall(getQuery());
+                                       cs.execute();
+                                       String results = "Executed";
+                                       res.setResponseData(results.getBytes());
+                               } finally {
+                                       close(cs);
+                               }
+                       // Insert/Update/Delete statement
                        } else {
                                int updateCount = stmt.getUpdateCount();
@@ -112,20 +121,8 @@
                } finally {
-                       if (stmt != null) {
-                               try {
-                                       stmt.close();
-                               } catch (SQLException ex) {
-                                       log.warn("Error closing statement", ex);
-                               }
-                       }
-                       if (conn != null) {
-                               try {
-                                       conn.close();
-                               } catch (SQLException ex) {
-                                       log.warn("Error closing connection", ex);
-                               }
-                       }
+                       close(stmt);
+                       close(conn);

@@ -164,6 +161,38 @@
                return data;

+       public static void close(Connection c) {
+               try {
+                       if (c != null) c.close();
+               } catch (SQLException e) {
+                       log.warn("Error closing Connection", e);
+               }
+       }
+       public static void close(Statement s) {
+               try {
+                       if (s != null) s.close();
+               } catch (SQLException e) {
+                       log.warn("Error closing Statement", e);
+               }
+       }
+       public static void close(CallableStatement cs) {
+               try {
+                       if (cs != null) cs.close();
+               } catch (SQLException e) {
+                       log.warn("Error closing CallableStatement", e);
+               }
+       }
+       public static void close(ResultSet rs) {
+               try {
+                       if (rs != null) rs.close();
+               } catch (SQLException e) {
+                       log.warn("Error closing ResultSet", e);
+               }
+       }
        public String getQuery() {
                return query;

$ svn diff >
$ cat
---    (revision 388876)
+++    (working copy)
@@ -50,7 +50,7 @@
                p.setValue(NOT_UNDEFINED, Boolean.TRUE);
                p.setValue(DEFAULT, JDBCSampler.SELECT);
-               p.setValue(TAGS,new String[]{JDBCSampler.SELECT,"Update Statement"});
+               p.setValue(TAGS,new String[]{JDBCSampler.SELECT,JDBCSampler.UPDATE,JDBCSampler.STATEMENT});

                p = property("query");
                p.setValue(NOT_UNDEFINED, Boolean.TRUE);


Good to know somebody read my post, and responded positively. The quickest way for patches is to log a Bugzilla request. Seemed somebody already had, so it was easy for me to just to contribute to Bug #38682

Withdrawl symptoms

I’ve recently started a new contract position, and the combination of more restrictive working hours, and at least 1 hour travel each way each day, has lead to me not being about to write like I have of late.

I seem to have far more draft blogs at moment, many things I want to write, and I have to temper this with a number of extra projects but I guess that’s life.

Emulating Oracle Output Functionality

Updated 28-mar-2006
There really is no way to do a comparision by numbers in features and functionality when it comes to Oracle and MySQL in the area of Stored Procedures and Triggers. Oracle does provide a far greater and extensive features list, however having more only means it has more.

We all know this, MySQL is a growing evolving database product, having just celebrated it’s tenth anniversary, Oracle on the other hand, will next year be 30, and has had significant funding in R&D being up until recently the second largest software company world wide. However, being open source, MySQL has the advantages of being lean and mean, providing only functionality users actually want and use, and has the community and organisation that is focussed clearly on providing new and improved functionality that users need.

I’ll have a lot more to speak about on this topic at my MySQL User Conference presentation MySQL for Oracle Developers next month, however in the preceeding weeks I thought I’d open some discussion and debate on various features, particularly in the area of Stored Procedures.

Here are some initial points, I’d like to talk about today. The purpose of this discussion is to highlight the difference between these two products, and possibilly other RDBMS products. While a RDBMS offers a feature, I am not stating that MySQL should necessarily also have this feature, however as part of comparing products in these articles, I am comparing existing Oracle Functionality to MySQL, so it will generally involve the description of functionality that is not presently comparable.

  1. Package Space
  2. Provider Supplied Procedures

1. Package Space

MySQL provides for Stored Procedures and Functions only the definition of individual procedures and functions. There is no way to group them into logical groupings.

Oracle provides the functionality of Package Space. Groups of procedures and functions can be defined within a package. Consider it like a wrapper of a group of procedures and functions. The package definition consists of 2 parts, the header section, which defines the scope of the procedures and functions, and the body which defines the actual procedures and functions. An added advantage of this that within Oracle you can protect your package body code (making it unavailable for view). I’ll discuss this more at a later time.

I’d like to see MySQL consider a package syntax particularly as businesses start to work more extensively with stored procedures and functions in larger enterprise applications. UPDATE: As stated by Roland in the comments, you can register your support for this functionality at MySQL under Bug #11696.

Within MySQL you can emulate package name, at least in syntax. You can use a dot ‘.’ within a procedure name, unlike this restriction for tables. The down side is the call must be quoted. I’ll discuss this more next.

2. Provider Supplied Procedures

Oracle provides an extensive list of supplied procedures and functions, defined in many packages. One of the earliest you learn in Oracle development is DBMS_OUTPUT.PUT_LINE. As the name indicates, this allows your to output a line of information. This is a common means of debugging output. Andrew Gilfrin post on Debugging Stored Procedures in MySQL raises this point, and an interesting solution using a debugging table. While this functionality works, one of my goals is to provide compability functions so that any migration of code could be simplified. Here is a much simplier solution.

$ more dbms_output.put_line.mysql
DROP PROCEDURE `dbms_output.put_line`
CREATE PROCEDURE `dbms_output.put_line` (output  VARCHAR(255))
  SELECT output;

A MySQL Usage:

mysql> CALL `dbms_output.put_line` ('hello world');

A comparision Oracle Usage:

SQL> DBMS_OUTPUT.PUT_LINE ('hello world');

This is as close the syntax can be. With MySQL you require the CALL and the backqoutes (`). Both things that can be easily added in an automated way.

DBMS_OUTPUT Note: this is a public web version of the Version 8i manual online. Oracle provides online documentation, but you require a login (which is free) to the Oracle Technology Network.

Oracle8i Supplied Packages Reference. Again this is dated information, being an older version, but gives you an indication. For reference Oracle 7 released in 1993 first provided Package/Procedure/Function functionality.


On a side note, I’d really like to see a IF EXISTS syntax for DROP PROCEDURE. IF EXISTS is an excellent MySQL extension. Oracle for stored procedures has the CREATE OR REPLACE syntax.

Just how many articles are at Planet MySQL?

I was trying to find an old article at Planet MySQL. One about a MySQL UDF to write to /var/log/messages. No luck.

Anyway, there is no search option on the site, and the latest addition of 10 entries per page makes it difficult to review pages. The RSS feed doesn’t give me a full option.

Anyway, it led me to look back in time to just how many articles are listed on Planet MySQL, and read some old stuff. I only came across it after I stumbled across the Brisbane MySQL Users Group back in Sep 2005.

Anyway the count was 2146. I’d like to see a stat on the home page of how many articles, and perhaps how many, last day, last week, last month.

MySQL Forge

I was reading Zack Urlocker’s MySQL Workbench Beta article and was keen to look at the Extensible architecture. Not much detail yet in the Figure Stylesheets, Scripts and Plugins, which will be good when it’s there, however it lead me to another secret.

The MySQL Forge. This was mentioned at the Brisbane MySQL Users Group Meeting with Brian Aker in January. There isn’t much content at present, but there is a Call for Content.

I don’t recall anybody blogging about it, or maybe I just missed it. Giuseppe Maxia should get his MySQL General Purpose Stored Routines Library up there. On that thought, I’ve been looking for a post several months ago, about a UDF that wrote to the system log /var/log/messages. Does anybody remember this?

Another dissappointing MySQL article

Another slightly disappointing article regarding MySQL, this one from a printed magazine. Below are my comments to the editor of Linux Format. The Dear Editor is an email link should others wish to make any comments. (Previous article comments What makes your blood boil?, Review of Database Magazine Article – “The Usual Suspects”)

Dear Editor,

I’ve recently subscribed to LXF, and have generally been very happy with the content in past months. I’m disappointed in your recent LXF77 article “Harness a database” Pg 57. Being a strong MySQL supporter, your article includes a number of practices which are less then ideal, and especially for the newly initiated, overly complicated when simplier alternatives exist.

I am happy to see that you had the current version 5.0.18. However in 7 years of using MySQL I’ve never had to compile from source, a binary has always been available, yet in your article you take the compile from source approach. While you may have done this to appease all possible readers of all POSIX variants, the binary for at least Linux could have been included.

In addition, much like your earlier article for Samba where you make reference to “most distros include this”, indeed MySQL is also included in most popular Linux distros.

You could have also made reference to the MySQL downloads area website. Infact, the MySQL 5.0 download area provides some 70+ dedicated distro versions for optimal usage. The site also states “For maximum stability and performance, we recommend that you use the binaries we provide.”

The second point that I do believe is completely unnecessary, and not recommended by MySQL, is the manual creation of user security. MySQL provides the CREATE USER command to achieve this. In your article, you would execute CREATE USER lxf@localhost IDENTIFIED BY ‘orangutan'; rather then an INSERT INTO user and a FLUSH PRIVILEGES.

Throughout your article you make no reference to the MySQL website, perhaps this is a policy, however it’s always ideal to have online references. At worst, a link to say (or appropiate) that provides links to the product information, in this case MySQL. This will allow you to undertake your necessary advertising, as well as track traffic.

I’m also sure, that contacting the MySQL Community Relations Manager for review of any MySQL content in future would be openly accepted, I’m even happy to review MySQL content in your magazine.

Atomicity, Consistency, Isolation, and Durability = ACID

ACID is the key transaction processing feature for a RDBMS. Without this, the integrity of the database cannot be guaranteed.

In Summary.

Atomicity is an all-or-none proposition.
Consistency guarantees that a transaction never leaves your database in a half-finished state.
Isolation keeps transactions separated from each other until they’re finished.
Durability guarantees that the database will keep track of pending changes in such a way that the server can recover from an abnormal termination.

A clearer definition from the Wikipedia.

  • Atomicity refers to the ability of the DBMS to guarantee that either all of the tasks of a transaction are performed or none of them are. The transfer of funds can be completed or it can fail for a multitude of reasons, but atomicity guarantees that one account won’t be debited if the other is not credited as well.
  • Consistency refers to the database being in a legal state when the transaction begins and when it ends. This means that a transaction can’t break the rules, or integrity constraints, of the database. If an integrity constraint states that all accounts must have a positive balance, then any transaction violating this rule will be aborted.
  • Isolation refers to the ability of the application to make operations in a transaction appear isolated from all other operations. This means that no operation outside the transaction can ever see the data in an intermediate state; a bank manager can see the transferred funds on one account or the other, but never on both—even if she ran her query while the transfer was still being processed. More formally, isolation means the transaction history (or schedule) is serializable. For performance reasons, this ability is the most often relaxed constraint.
  • Durability refers to the guarantee that once the user has been notified of success, the transaction will persist, and not be undone. This means it will survive system failure, and that the database system has checked the integrity constraints and won’t need to abort the transaction. Typically, all transactions are written into a log that can be played back to recreate the system to its state right before the failure. A transaction can only be deemed committed after it is safely in the log.


This fad started many years ago, and once I achieved it. Well today, I got the google 1 of 1 result. Here are the rules

GoogleWack “Your goal: find that elusive query (two words – no quote marks) with a single, solitary result!”

And my two words were:

ensureClassInitialized xmlbeans

Of course the problem is, by the time you read this, it may no longer be a 1 of 1 result, as my Blog may get referenced. So, I’ve attached a screen print for proof. (yes, it’s an undoctored screen print)

dbus messaging error under CentOS 4.2

The Problem
I’ve been getting the following /var/log/messages errors:

Mar 13 21:38:42 lamda dbus: Can't send to audit system: USER_AVC pid=3606 uid=81 loginuid=-1 message=avc: denied { send_msg } for scontext=user_u:system_r:unconfined_t tcontext=user_u:system_r:initrc_t tclass=dbus
Mar 13 21:39:17 lamda last message repeated 7 times

Based on the command dbus-launch – Utility to start a message bus from a shell script. Investigation found the process running under my userid, not root?

rbradfor 5760 1 0 Mar11 tty1 00:00:00 /usr/bin/dbus-launch --exit-with-session /etc/X11/xinit/Xclients
rbradfor 5761 1 0 Mar11 ? 00:00:00 dbus-daemon-1 --fork --print-pid 8 --print-address 6 --session

The service can be stopped which addresses the immediate problem.

/etc/init.d/messagebus stop

The Fix

$ wget
$ wget
$ rpm -Uvh policycoreutils-1.18.1-4.9.i386.rpm selinux-policy-targeted-1.17.30-2.126.noarch.rpm

CentOS 4 Forum Reference

Beating those annoying telephone menus

Everybody hates having to listen to automated telephone systems, with long menu options, and you just want to speak to a human, even to be redirected to another human. I can’t count the number of times I’ve been in the menu system for 30 mins. I’ve even been lost in the menu system with Telstra, finally hung up in discust, redialed and been almost immediately serviced.

So Apparently if you ring a Telstra number and receive voice prompting do the following to get to an operator quicker:

1. Say a word ie “mobile” or “phone”
2. Press the hash (#) key
3. Wait for the recorded message
4. Press the hash key again

Apparently this will put you at the top of the queue for the next available operator.

We just tested this with the 13 2200 number and it seems to work. After step 4, we were sent to a human operator within 15 seconds. Nice.

Well Emptorium Australian Banking Cheat Sheet will get back at big business with a number of cheats.

Bank Phone Shortcut
AussieHomeloans 13 13 33 0000
American Express 1300 132 639 0#
ANZ Bank 13 13 14 00000
BankWest 131 718 00000#
Bendigo Bank 1300 366 666 0
Citibank 13 24 84 00
Commonwealth Bank 13 22 21 000
Diners Club 1300 360 060 0
Esanda 13 23 13 00
HSBC 1300 308 880 1
ING Bank 1800 639 082 0 wait 0#
ING Direct 1800 500 240 0
National Australia Bank 13 13 12 ###
RAMS Home Loans 13 72 67 000
Suncorp 13 11 34 0000
St. George Bank 13 33 30 say ‘Everyday Banking’
Wizard Home Loans 131 970 0
Westpac Banking Corporation (Mortgage Sales) 13 19 00 0
Westpac Banking Corporation (Phone Banking) 13 20 32 00*0
Woolworths Ezy Banking 13 72 88 0

Testing a new MySQL Transactional Storage Engine

As part of my A call to arms! post about a month ago, I’ve had a number of unofficial comments of support. In addition, I’ve also been approached to assist in the completion of a MySQL Transactional support engine. More information on the PBXT engine will be forthcoming soon by it’s creator.

Anyway, I’ve taken on the responsiblity of assisting in testing this new storage engine. This will also give me the excuse of being able to pursue some other ideas about the performance of differing storage engines for differing tables in business circumstances, such as MyIsam verses InnoDB in a highly OLTP environment. Part of testing will be ensure ACID conformance in varying situations and multi-concurrency use. Of course the ability to also do performance and load testing would be a obvious extension.

Considering how I’m going to benchmark is an interesting approach. I of course want to use Java, my choice of language at present. This presents a problem, in another factor towards performance, however by using Java, I’m simulating a more real world environment of a programming overhead and JDBC Connector rather then just raw performance output.

Laying out a plan would include an ability to have an existing database structure and data, be able to bulk define SQL statements and transactions, and parameterise SQL during transactions. I would need to be able to verify the state of database from the transactions, and clearly identify any invalid data. I would also need the ability for handling threads, and of course adequate reporting of my results.

As of MySQL 5.1.4, there is a supported benchmarking tool called mysqlslap in MySQL. I’ve discounted using this because I figured at this early stage, the documentation and exposure of this is of course limiting, and I’m sure I’d still need to perform other development.

Along comes JMeter. Within Java development I use JUnit quite extensively. This is key in the test-driven agile methodology approach of Extreme Programming. In discussion with this problem with a collegue on a new project, I found that JMeter was used for extensive load testing for web applications, but also performed database testing, and provides the support to integrate JUnit tests.

So yesterday I had a quick look at JMeter. The capabilities for defining, reporting and threading are quite complete. It took litterally minutes to install, configure, run an initial test and view results all in a GUI interface. A little more work gave me scripting handling of my initial tests. I’ve posted my initial investigations of JMeter – Performance Testing Software and JMeter and Ant Integration earlier.

With this behind me, I’ve just got to define the approach for more complete transactional tests, explictly confirming the results (I’m hoping to achieve this in custom JUnit tests). If I can solve this, then I can spend the most of time in the defining of adequate tests. Let’s see what the next few days work provides.

JMeter and Ant Integration

Using Ant withJMeter you can achieve remote running and web based reporting.

I got the ant-jmeter.jar and sample results output .xls from Embedding JMeter with Ant. JMeter Ant Task

cd /tmp
mv ant-meter.jar $ANT_HOME/lib

Within a new project directory, place your saved JMeter Tests (*.jmx) in a loadtests subdirectory, and the downloaded jmeter-results-report.xsl in the project directory.


<project name="dbtest" default="dist" basedir=".">

<property name="base.dir" value="."/>
<property name="report.dir" value="report"/>

<taskdef name="jmeter"
<target name="dist" depends="runtest,testresults" />

<target name="runtest" description="Run jmeter tests">
        <jmeter jmeterhome="/opt/jmeter"
                <testplans dir="${base.dir}/loadtests" includes="*.jmx"/>

<target name="testresults" description="Report Test Results" depends="runtest">
        <delete dir="${report.dir}" quiet="true"/>
        <mkdir dir="${report.dir}" />
        <xslt in="${base.dir}/loadtests/JMeterResults.jtl"

Report output from running ant can be found at report/JMeterResults.html

JMeter – Performance Testing Software

Apache JMeter is a 100% pure Java desktop application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions. Specifically it provides complete support for database testing via JDBC.

Some References: Homepage  ·  Wiki Page  ·  User Manual

Initial Installation Steps

$ su -
$ cd /opt
$ wget
$ wget
$ tar xvfz jakarta-jmeter-2.1.1.tgz
$ tar xvfz jakarta-jmeter-2.1.1_src.tgz
$ ln -s jakarta-jmeter-2.1.1 jmeter
$ echo "PATH=/opt/jmeter/bin:$PATH;export PATH" > /etc/profile.d/
$ . /etc/profile.d/
$ jmeter &

Adding MySQL Support

cd /tmp
tar xvfz mysql-connector-java-3.1.12.tar.gz
cp mysql-connector-java-3.1.12/mysql-connector-java-3.1.12-bin.jar /opt/jakarta-jmeter-2.1.1/lib/

Steps to perform simple MySQL JDBC Test.

1. Launch JMeter
2. Add a new Thread Group (using right click)
3. Define Thread Settings (no messing around 3 threads x 1000 iterations)
4. Add a Sampler JDBC Request
5. Add initial sample SQL query
6. Add a JDBC Connection Configuration
7. Define JDBC Connnection details (I’m using the sakila sample database at this time)
8. Define a Results View
9. Run the sucker

This is just a quick intro to prove it all works, There are quite a lot of reporting output possible, something for my next post.
Click on Image for a larger view.

Using Parrallels as a VM for Windows

$ su –
$ Parallels-config
Configuring Parallels Workstation 2.0 build 1514
Configuring Parallels Workstation 2.0 drivers…
Compiling Parallels Workstation 2.0 drivers…
Drivers have been compiled successfully.
Installing drivers…
Starting drivers…
Load Parallels Workstation 2.0 hypervisor …
Load Parallels Workstation 2.0 vm-main …
Load Parallels Workstation 2.0 vm-bridge …
Load Parallels Workstation 2.0 vmvirtualnic …
Configuration completed successfully
Now you can run Parallels Workstation 2.0
Issue “Parallels” command.

You have an interface now to configure your Virtual Machine settings, including memory and disk very easily.

Some observations.
The install process is more true Windows XP, format drive, reboot, all options etc. With Win4LinPro a lot of this was shielded (which was impressive in itself).

The Parallels VM runs in it’s on window, but you get locked in when you mouse click to focus. Using Ctrl-Alt, your focus is returned to your host environment.

Parallels is clearly a more rounded product, providing many more host environments. The interface provides a lot more virtual feel. You have Disk/CD/Network/Sound icons embedded in the window

In this install sound also worked by default, it did not in Win4LinPro. The playing of audio was actually a good indicator during the Windows activation process (which wasn’t in Win4LinPro) as you could here the delays in extensive CPU processing.

Parallels required you to run as root, while Win4LinPro disallowed root invocation. You were also given the opporunity to configure Windows users, while in Win4LinPro it just masked an administrator behind the scenes.

In defense of Win4Lin Pro, it clearly took away a lot of steps in the normal windows installation which made it clearly easier to install.

For Win4Lin Pro, it would not accepted my laptop Windows XP Pro CD (as it was not SP1 or SP2).
The specs for Parallels stated it would work, however I used anothe Windows XP Pro CD with SP1.
Surprisingly in the activation process, I could not use the Serial Number for my Laptop Windows XP, I had to use the serial Number for my SP1 CD. Not to bother, I own both, and use neither, it was just interesting to see Microsoft reject a valid serial number.

Latest MySQL Versions under VMWare

I made reference previously to Testing/Trialing new MySQL Releases using VMWare.

Well, I’ve just about completed my own Image for the lastest MySQL 5.0 (given I’m now running MySQL 5.1). I’m interested in sharing my experiences, and even providing some images for users if there is any demand out there.

What I’ve decided on is to use the VMWare supplied Browser Appliance which is Ubuntu 5.10. The great thing is the image autoboots into graphical mode, auto logins and loads a browser. My goal now is to get a suitable startup page describing the MySQL environment, links, manual etc.

The only requirements to run would be the Free VMware Player and a latest image.

I’m looking at providing a FTP and RSYNC download. Those savvy people will benefit a lot more from RSYNC when the image is upto 500MB.

I’m interested to know if anybody else would use this with the lastest 5.0, 5.1, 5.2 etc versions. Also, would it be of benefit to include other MySQL products such as Query Browser, Administrator, Workbench.

Check out the Innodb Site?

Have a look at InnoDB. Well, ok your lazy, so here’s a screen print below.
Plastered thoughout the top section is the word MySQL. It’s in the core banner blurb, there’s a logo, and even links to the MySQL Documentation. And right in the middle of all this is “Innobase OY is an Oracle Company”, with the standard Oracle Logo.

So my question would be, is this a good thing or a bad thing from a MySQL advertising perspective?
Does it help or hinder MySQL?
Does it show Oracle as being in partnership with MySQL? Is this good for MySQL to increase it’s exposure into the Oracle world?
Does inclusion of InnoDB now within Oracle traffic and links improve exposure to MySQL within search engines?

Frankly, I’m a little surprised that Oracle Legal hasn’t got onto this, I’m sure somewhere there would be a decree, that no competitor logos should be shown with the official Oracle logo.

I’d suspect that the existing MySQL community know the deal re Oracle, so perhaps this will expose more Oracle specific people to MySQL!

Oracle Comments

Some recent posts regarding Oracle (See Smart moves by MySQL AB and Larry Ellison still doesn’t understand open source) leads me to put in my 2 cents worth.

My background I’m sure like a lot of experienced MySQL people is in Oracle, and indeed in Ingres before that (starting in 1988). I have also worked for a number of years at Oracle Corporation. Ironically I started as their resident Ingres Specialist, in an international research project of DMS (Design & Migration Services) of re-engineering Ingres applications into an Oracle Designer Repository some 10 years ago in 1996. I of course moved into a number of other Oracle roles for clients following that. I still retain some contacts around the place.

It’s obvious Larry’s goal is to become more “Open Source”. This is of course a complex topic, and you can’t just say it like this. I’ll leave that for another day, but I’ve got some opinion on current trends.

It’s clear from recent purchases of JBoss, and SleepCat (Berkley DB) that Oracle has an intention of providing a suitable technology stack in a number of vertical marketspaces that Oracle presently cannot. For example, in the embedded space. Purchasing provides a much quicker solution, and also provides a different way to solve the problem instead of the legacy Oracle Product line. I haven’t seen any recent press, but I know that Xen was also in Oracle’s wallet space.

I would suspect that Oracle will move to providing a Stack solution (akin to SpikeSource for example) in a number of vertical spaces. These stacks will include non-traditional but now owner Oracle products, including Berkeley DB in lower end solutions. This along with the recent Oracle Express Edition (XE) free offering will enable Oracle to target market’s that were previously unavailable.

This is clearly not for a financial intention. There is no way to obtain a return on investment, however it’s all about upselling. By providing these offerings, Oracle now has a large marketplace to promote commercial product offerings.

Assuming, Oracle goes down this path, I’d assume they will also provide clear migration paths between stack offerings, as part of upselling. This will be more complex to achieve. I also suspect that Oracle will move towards a better Web 2.0 model, by providing products are no cost, but provide a service to support and maintain in these new marketspaces.

In closing, why did Oracle purchase InnoBase, the creators of the MySQL InnoDB Storage Engine? This question seems still unanswered. It doesn’t fit easily into the above ideas of differing technology stacks. Ultimately, money buys power, and I suspect it was just that, with no real future intentions or clear plan.

Thanks for the comment about JBoss, yes, it’s not official, nor is Xen, but it took Oracle I think 15 months to get Peoplesoft.

I came across the Oracle Corporation Wikipedia entry in other work, the end of the history page reads a who’s who of acquisitions.


We all know Tux as the Linux penguin, and those that know me, understand how much I hate Microsoft, and that my core logo, as shown down the right of my blog with Windows Sucks is what I preach. Well I’ve now had this made into a logo on tee-shirts.

As part of searching for images, I’ve come across a few alternative images that I really like, Tux and the BSD demon, Tux and the loosing Windows and MSN logo. You can find more of my collected works at Tux Images