Tips and Tricks » MySQL

MySQL password hashing

admin — Fri, 02 Jan 2009 18:55:53 +0000

Whenever you upgrade your MySQL installation, make sure to upgrade any client that uses it.

In some cases, clients that use a version prior to 4.1 will have a problem authenticating against the MySQL database if the latter has a post 4.1 version.

The trick is that after 4.1 (i.e. 4.11 and up), MySQL changed the way it stores the passwords in the user table inside the mysql system database.
Password hashes are now 41 bytes long instead of the old 16 bytes.

So for example, if your MySQL server is 5.0, while your php-mysql library is 4.1, your web …

Setting up MySQL database replication

admin — Mon, 15 Sep 2008 18:50:23 +0000

It’s always about data. What’s the use of any system without the data it relies on?

Setting up a database replication is one of many steps that should be taken in order to preserve data, preventing any loss and making disaster recovery easier.

Luckily, it’s easy with MySQL. So let’s suppose we have two servers running MySQL, one called host1 and the other host2.
Replication can be either master-master or master-slave. With a master-slave replication, the slave always replicates what the master database is executing. In master-master replication, both databases synchronize with each others.

For the purpose of this tutorial, …

Resetting your mysql root password

admin — Thu, 17 May 2007 08:10:46 +0000

It is quite frequent that an administrator simply forgets his mysql’s root password.

Luckily, it is quiet easy to reset it, here are the steps:

SSH as root to your machine
Turn off the mysqld daemon if running

RedHat/Fedora users can do so by executing:Â service mysqld stop

Run safe_mysqld by executing:

safe_mysqld –skip-grant-tables
(this will run allow you to connect without a password)

Open a second shell / SSH again and execute:

mysql mysql
(to directly connect and select the mysql database which contains the user authentication data)

On the mysql prompt, execute:

update user set password=password(‘newpassword’) where user=’root’;

How to import a csv file into mysql from the prompt

admin — Thu, 11 Jan 2007 17:40:02 +0000

For the follows out there who do not know how to import coma separated data into mysql from the prompt, here it is:

Assume:

PATH is the path to the csv file (can be relative to the directory you were in before logging into mysql)
TABLE is the table name that you have already created and whos fields match the csv file fields.
USERNAME is the mysql user that have access to insert data into TABLE
DATABASE is the database containing that table

- login to mysql by typing: mysql -u USERNAME -p DATABASE
The prompt will ask you for …