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Displaying posts with tag: command-line (reset)
In a proxy-ed world, where do connections come from?

Overview The Skinny

Database Proxies provide a single entry point into MySQL for the calling client applications.

Proxies are wonderful tools to handle various situations like a master role switch to another node for maintenance, or for transparency with read and write connections.

However, when the time comes to perform the switch action, all of the calling clients have been funneled through the proxy, so identification of the calling host from the database itself becomes difficult.

The Problem What is going on?

Let’s illustrate how not knowing the source of a client connection can be an issue for the database administrator…

In the following diagram, three client applications connect to a Tungsten Cluster via the Connector proxy:

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Slick Command-Line Tricks for a Tungsten MySQL / MariaDB Database Cluster

Overview The Skinny

Tungsten Clustering provides high availability, disaster recovery, and a host of other benefits for MySQL / MariaDB / Percona Server databases. In this blog post we will explore some of the shell aliases I use every day to administer various Tungsten Clusters.

Shell Aliases: A Quick Review Quick and Easy

A shell alias is simply a way to create a shortcut for frequently-used command sequences.

For example, I like to shorten the command clear to cls, i.e.

shell> alias cls=clear
shell> cls

If you create an alias on the fly it will be lost when the shell exits.

To save aliases so they are available to all shell sessions, update your shell’s profile or rc script.

For example, add the below line to the bottom of …

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Performing an Unattended Uninstall of MySQL in Windows

The MySQL Installer is an easy way to install and maintain your MySQL installations on Microsoft Windows.

It comes not only with the database server and documentation, but also with the underrated MySQL Workbench, and various connectors and support utilities such as MySQL for Excel. Modifying the installed products or uninstalling them is also fairly straightforward: 

 Start -> All Programs -> MySQL -> MySQL Installer -> MySQL Installer

This launches the Maintenance window of the Installer GUI, and gives you the options:

  • Add/Modify Products and Features
  • Check for Updates
  • Remove MySQL Products. …
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The Little Things

It’s always the little things in life. One of the things that has been a very “little thing” that causes a lot of frustration while writing The MySQL Administrator’s Bible is the prompt. Specifically, the fact that you can only change the first line of the prompt, but not the subsequent lines.

The default prompt that appears on the first line of the prompt is:
The default (and unchangeable) second line of the prompt is four spaces followed by an ASCII arrow:


The second line of the prompt is hard-coded to match up very nicely with the first line in a fixed-width font:

mysql> SELECT
    -> 1+2;

However, you can change the prompt, which is pretty handy:

mysql> prompt \d:
PROMPT set to '\d: '
(none): use test;
Database …
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Showing entries 1 to 4