Une soirée de conférence et networking intitulée: "MySQL, le Cloud et MariaDB" Invitation - Meetup SkySQL

Mercredi 12 décembre 2012 de 19h à 22h30

SkySQL Ab vous invite à une soirée de conférence et networking intitulée :

« MySQL, le Cloud et MariaDB »

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If you are interested by a great and revolutionary HA solution for MySQL or even if you already have some experience with PXC and/or Galera, I invite you to attend the tutorial I will deliver in Percona Live MySQL Conference London 2012 (PLUK2012), December 3rd : Percona XtraDB Cluster in a nutshell.

Small amount of theory and a lot of exercises and examples to really tame the beast that PXC is !

A Codership engineer will also be present and happy to help me answering your questions.

Note to attendees: please bring your laptop with a recent Virtual Box installed and enough free space to store 3 VMs (+/-2G per VM). As said …

Dawnstar Australis (yes, nickname – but I know him personally – he speaks with knowledge and authority) updates on The Real Victims Of The Click Frenzy Fail: The Australian Consumer after his earlier post from a few months ago.

Colourful language aside, I believe he rightfully points out the failings of the organising company and the big Australian retailers. From the Open Query perspective we can just review the situation where sites fall over under load. Contrary to what they say, that’s not a cool indication of popularity. Let’s compare with the real world:

1. Brick & Mortar store does something that turns out popular and we see a huge queue outside, people need to wait for hours. The people in the queue can chat, and overall the …

I have addressed previously how multi-node writing causes unexpected deadlocks in PXC, at least, it is unexpected unless you know how Galera replication works.  This is a complicated topic and I personally feel like I’m only just starting to wrap my head around it.

The magic of Galera replication

The short of it is that Galera replication is not a doing a full 2-phase commit to replicate (where all nodes commit synchronously with the client), but it is instead something Codership calls “virtually synchronous” replication.  This could either be clever marketing or clever engineering, at least at face value.   However, I believe it really is clever engineering and that it is probably the best compromise for performance and data protection out there.

…

I would like to make a quick MySQL 101 about numeric types in MySQL and especially explain the difference between the numeric type attributes and the maximum value that a numeric type can store.

Someone asked me yesterday why when he inserts a value in a table, the value 127 appears instead of the value 160 that he’s just inserted.
Ok, let me explain, consider this table :

What happens if you want to insert this row in the table :

sql > insert into product values (160, 554, "iPad mini");
Query OK, 1 row affected, 1 warning (0.01 sec)
sql > show warnings;
+---------+------+---------------------------------------------+
| Level   | Code | Message                                     |
+---------+------+---------------------------------------------+
| Warning | 1264 | Out of range value for column 'id' at row 1 | …

It started with a tweet from a coworker asking if I can recommend reading for making a master/master MySQL server. There are plenty of caveats about writing to only one master at a time, and that master/master is not write scaling, but I think I tackled it pretty well in the MySQL Administrator’s Bible. It is not a very long topic, so I made a PDF of the relevant pages. High Performance MySQL also has a few pages that I would recommend reading, and the third edition has similar information as the Bible, although it goes into more detail about why you might use master/master replication and what might go …

It started with a tweet from a coworker asking if I can recommend reading for making a master/master MySQL server. There are plenty of caveats about writing to only one master at a time, and that master/master is not write scaling, but I think I tackled it pretty well in the MySQL Administrator’s Bible. It is not a very long topic, so I made a PDF of the relevant pages. High Performance MySQL also has a few pages that I would recommend reading, and the third edition has similar information as the Bible, although it goes into more detail about why you might use master/master replication and what might go …

Just setting up MySQL replication is not enough, you would need to periodically monitor your slaves to ensure they continue to work seamlessly. Here is a basic overview of the Slave variables to monitor and the tools that will help you monitor those with ease.

Top variables to monitor on your slaves

Replication is best monitored by checking the following variables-

1. SLAVE_RUNNING: This is a global status variable and its value can be checked using SHOW GLOBAL STATUS like 'slave_running'. It can either be ‘ON’ or ‘OFF’.

   If slave_running is ‘ON’, then the slave is up and working fine, which means both the SQL thread and the IO thread are running. If either the SQL thread or the IO thread is not running then this variable would be ‘OFF’. Use SHOW SLAVE STATUS and try to determine whether there was an error or the slave was stopped manually. Check …

Backup is one of the most important, part of the database administration. There are several ways to backup MySQL data. I'm discussing a very simple script, easy script  to take backup of multiple databases. This script can be customized as, per the requirement.

Script

#!/bin/bash
     
    MyUSER="backup" # USERNAME
    MyPASS="backup_pass" # PASSWORD
    MyHOST="localhost" # Hostname
     
    # Linux bin paths, change this if it can not be autodetected via which command
    MYSQL="$(which mysql)"
    MYSQLDUMP="$(which mysqldump)"
    CHOWN="$(which chown)"
    CHMOD="$(which chmod)"
    GZIP="$(which gzip)"
     
    # Backup Dest directory, change this if you have someother location
    DEST="/backup"
    
    Month="$(date +"%b")"
    Day="$(date +"%a")" 
    # Main directory where backup will be stored
    MBD="$DEST/data/$Month/$Day"
     
    # Get hostname
    HOST="$(hostname)"
     
    # Get data in dd-mm-yyyy …

SkySQL’s live in the UK – come and check us out at Oxford University - devfest

There will be a nice contrast in the air as the ancient institution of Oxford University plays home to the latest trends in open source software at the All Your Base conference, taking place at the Said Business School on the 23rd November. And we are prepared to show off our new Cloud and Enterprise products, allowing developers to get hands-on with the solutions.

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