The latest from the MySQL community

Ayer por la tarde se hizo la 2ª reunión de Madrid MySQL User Group. Para todos los que están en Madrid o cerca, os animo a ir, a compartir experiencias, dudas, cuestiones, etc. alrededor del tema “MySQL”. No tengais miedo!

Si os apetece apuntaros al siguiente (fecha pendiente por ahora), mirad a ver http://www.meetup.com/Madrid-MySQL-users-group/.

Ánimo.

Ayer por la tarde se hizo la 2ª reunión de Madrid MySQL User Group. Para todos los que están en Madrid o cerca, os animo a ir, a compartir experiencias, dudas, cuestiones, etc. alrededor del tema “MySQL”. No tengais miedo!

Si os apetece apuntaros al siguiente (fecha pendiente por ahora), mirad a ver http://www.meetup.com/Madrid-MySQL-users-group/.

Ánimo.

On Tuesday Sept.10 I went to PHP TechTalks with Rasmus Lerdorf, Sebastian Bergmann, and Stig Bakken. Great initiative by Stig Bakken @ Zedge. The TechTalks focused on new features and best practices and for PHP 5.4 and 5.5.
Great feeling of going to the roots of LAMP and MySQL. Thanks for the invite Stig!

(For more have a look at https://zedgetechtalksphp.eventbrite.com/).

So it’s all well and good having a nice MySQL cluster running on some tiny hardware, but what can you do with it?

Well in order to demo the software at some upcoming techtours my colleague put together a little Java application to showcase what can be done.

I want to run my raspberry pi’s headless so in order to get this to work I needed to install a vncserver

sudo apt-get install tightvncserver

Once this is installed make a note of the display you set up and check you can connect to it via a vnc client.

Install the java application

configure the config file for the MySQL credentials

Run the java application in a shell window on the remote VNC session making sure the screen variable has been set accordingly

export DISPLAY=1:4

When you have it all working it should look like the following

…

I thought it would be nice to have a display on pi1 (the primary node) so found an LCD kit that hopefully I could write a little script to hack around to display the status of each data node.

So I purchased the Adafruit Char 16×2 LCD Plate from:

https://www.modmypi.com/raspberry-pi-expansion-boards/raspberry-pi-blue-and-white-16×2-LCD-kit

Then set about soldering it all up

tada!

I followed the guide here:

…

So you’ve done all the hard work, now what?

We need to test that everything is working. Ie:

• That the Management Daemon can see the NDB instances.
• That the NDB instances are running on the two cluster nodes
• The MySQL client can connect and talk to the NDB presented tables

start the MySQL client

and execute the following command to show available NDB nodes:

show global status like 'ndb_number_of%';

mysql -uroot -p[password you set when first running mysql]

root@cgepi1:/var/lib/mysql-cluster# mysql -uroot -phelpdesk
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.25a-ndb-7.3.0-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may …

Starting the services

MySQL Cluster Management Daemon (ndb_mgmd)

I prefer to start stuff manually for demos as my poor little brain likes to know what is running and how they started.

Starting the management Daemon

ndb_mgmd -f /var/lib/mysql-cluster/config.ini –configdir=/var/lib/mysql-cluster  –ndb-nodeid=1

Should give you an output similar to:

MySQL Cluster Management Server mysql-5.5.25 ndb-7.3.0

You can check its running with a ps -aux | grep mysql and check for the ndb_mgmd process

root     16868  3.2  0.6  30692  2804 ?        Ssl  13:17   0:03 ndb_mgmd -f /var/lib/mysql-cluster/config.ini --configdir=/var/lib/mysql-cluster --ndb-nodeid=1

MySQL NDB Service

As root or sudo

sudo /usr/local/mysql/bin/ndbd &

you should get the following output:

2013-09-02 …

Ok so before we go any further I guess I should draw a little picture (I hate using visio so he’s my best drawing)

So on ‘pi1’ we’ll be configuring the following services:

ndb_mgmd (MySQL Management Service Daemon) – monitors the MySQL Cluster

ndbd (Network Database Daemon) – The Network database storage engine

mysqld (MySQL client) – The client allowing you to query the database.

On pi2 we are just running the NDBD Daemon

So we need to configure the ndb_mgmd daemon. Ie tell it where the two data nodes are and how to connect. 

mkdir …

So there are a few prerequisite’s to install first Update everything

apt-get update

Install libncurses and openjdk

apt-get install cmake libncurses5-dev openjdk-7-jdk

Set the swap size to 2GB sudo dphys-swapfile swapoff sudo vi /etc/dphys-swapfile  =>>  CONF_SWAPSIZE=2048 sudo dphys-swapfile setup sudo dphys-swapfile swapon

Install mysql cluster (get source from http://dev.mysql.com/downloads/cluster/7.3.html#downloads)

cd /usr/local/src
tar xzfv /home/pi/mysql-cluster-gpl-7.3.0.tar.gz
cd mysql-cluster-gpl-7.3.0

Patch MySQL to workaround a pointer type bug with ARM chipsets (get patch from http://bugs.mysql.com/file.php?id=17637)

cd sql-common
patch -l -f …

So my colleague Andrew Morgan did this a year or so ago, but I wanted to repeat his experiment and add a few features in order to make it a live demo. It should show how MySQL Cluster (CGE) can run even on very modest hardware..

The hardware has been purchased

2x Raspberry Pi’s (model b)

1x Adafruit LCD Pi Plate (16×2 LCD)

USB Hub for power

HDMI -> DVI adaptor

Netgear 100/Mbs Switch

 
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