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Displaying posts with tag: Databases (reset)
Search and replace in MySQL

I recently had to help a friend go through a site and correct alot of wrong URLs. Here is an easy way to do search and replace in MySQL, for those of you who didn’t know.

If you have phpMyAdmin you can use the SQL-tab to run this query. If not, you can run it from the commandline as well. Here is the query I ran: (remember of course to replace table_name, column_name, find_this and replace_with_this with real data)

UPDATE table_name SET column_name = replace(column_name,"find_this","replace_with_this");

[tags]MySQL,databases,sql,query[/tags]

Issues with InnoDB in 5.1!
Unexplained replication authentication behaviour

I’m playing with the latest 5.1.11 beta in a master/slave replication situation. Given a lack of H/W lying around I’m configuring a mixed H/W setup to leverage an existing office’s after hours CPUs running Windows XP for my slaves. So here is my test setup.

Server

Linux - 192.168.100.170

The following are the relevent my.cnf settings

[mysqld]
port=3307
server-id = 1
log-bin=mysql-bin

Confirming the server. I did some test commands prior to confirm the position.

$ mysql -uroot -p mysql
Your MySQL connection id is 47 to server version: 5.1.11-beta-log
mysql> show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 |     1759 |              |                  | …
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Mercurial Version Control Software

I got asked (being a Java developer) about what was involved in creating an Eclipse Plugin for Mercurial. Well in true Google style, why invent when somebody probably already has. A quick check finds Mercurial Eclipse by VecTrace.

Now until last week, I’d never heard of Mercurial, so this is really an introduction to somebody that has no idea.

What is Mercurial?

Mercurial is a fast, lightweight Source Control Management system designed for efficient handling of very large distributed projects.

Ok, so big deal, I use CVS. I also use Subversion (SVN) for my Apache contributions, and also for MySQL GUI products. Why do we need another Version Control Product? Mercurial is a Distributed Software Configuration Management Tool. …

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What is software quality?

Greg Lehey wrote today Is MySQL getting buggier?. The underlying question of his comments is a more fundamental and passionate topic, and especially for me. That is “Software Quality”.

The quintessential question is this. “How do you determine the ’software quality’ of a product?” And then quickly followed by, “How do you benchmark this with other software products?”

The short answer to second question is simple. You can’t. The reasons why become apparent in addressing the first question. (There’s a mathematical term for this two question situation, another one of the million things to research and remember one day).

15 years ago as part of my masters research I worked on “Improving Software Quality and Software Productivity”. At the time when I started, I found that these were generally considered …

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Using PBXT 0.9.5

Paul has released Version 0.95 of his PBXT MySQL Transactional Storage Engine.

Here is what I did to get it operational under CentOS 4.3.

su -
useradd pbxt
su - pbxt
wget http://www.primebase.com/xt/download/mysql-4.1.16-pbxt-0.9.5.tar.gz
tar xvfz mysql-4.1.16-pbxt-0.9.5.tar.gz
cd mysql-4.1.16-pbxt-0.9.5
./configure --with-debug=full --with-pbxt-storage-engine --without-query-cache --with-mysqld-user=pbxt  --prefix=/home/pbxt/mysql
make
make install
scripts/mysql_install_db
cd /home/pbxt/mysql
./bin/mysqld_safe --user=pbxt --basedir=/home/pbxt/mysql &

Now, lets test and confirm PBXT is operational.

bin/mysql -uroot mysql
Reading table information for completion of table and column names
You can turn off this …
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Using Cascade in Foreign Keys

For those that are using a Referential Integrity based Storage Engine in MySQL, the use of Foreign Keys can provide an extra level of data integrity within your application. There are of course caveats to this statement, such as correct design, proper transactional use etc, but that’s a topic for another time. The use of CASCADE has an effect on this.

So, just a quick refresher, using the MySQL Sakila Sample Database (if you don’t have it, get it. This can be a valuable tool in many other areas). Let’s first check out the Schema Diagram. We will …

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What constitutes a good error message to the user?

Today, will go down in my professional history as quite possibly the lowest I would ever think of a software developer. I’ve carefully avoided the term “fellow coder”, speaking of a IT industry sticking by fellow IT people, but not today.

I presently support an existing production system, some 1000+ users that’s been in place around 3 years in which I’ve had no prior involvement until recently. Integration with other external parties within the system have provided an esclation in errors being reported in this external communication, and lack of adequate feedback to the user is another topic. Email is the means of reporting administratively of user errors, again another topic of issue. Within these emails, which are almost impossible to manage due to the limited internal GUI only toolset and lack of access to actual email account files to automate scripting (yet another topic? Do you see a trend here), is some relevent information …

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Major rewrite of C/ODBC completed

One of my first major tasks at MySQL has just been completed - a major rewrite of the Connector/ODBC (C/ODBC) documentation.

There were three major focuses for the rewrite:

  1. Bring the documentation up to date. We had a mix of information on the latest release (currently 3.51, but 5.0 is currently in development), but many of the sections didn’t reflect that new version. There is also new information on how to install the driver on Mac OS X.
  2. Restructure the information. This is something I’m doing across the board on the Connectors docs, as I try to re-organize them all into a more coherent, and compatible, structure. For example, I’ve collated all of the tips about using C/ODBC with different applications into their own section, organized by application. I’ve also extended the information; for example we now have a …
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MySQL Performance Blog - Great resource for MySQL DBAs

At this week I came across great blog of Peter Zaitsev and Vadim Tkachenko - two developers from High Performace Group at MySQL Inc. This blog’s name is MySQL Performance Blog and, as you probably assume, it is about misscelaneous sides of MySQL optimization and related stuff. So, if you are MySQL administrator or, even, developer, that works with MySQL, I would advise you to take a look at this blog - there are lots of useful MySQL optimization info.

Tags: mysql, high, performance, …

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