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ScaleArc’s iDB Reviewed


Indexed CSV


Install HandlerSocket into CentOS 6.2 MySQL

If you don’t know what HandlerSocket is read Yoshinori Matsunobu’s blog post.

Because I’m starting with a minimum install of CentOS 6.2,  You’ll need to make sure you have a few utilities and development tools installed:

yum install git perl openssl-clients wget telnet lsof  
yum install gcc gcc-c++ libtool make openssl-devel perl-DBI perl-DBD-MySQL.x86_64

Installing the MySQL source

You’ll also need the MySQL source and a few more supporting packages.

yum install rpm-build gperf readline-devel ncurses-devel time perl-Time-HiRes 
rpm -i …
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New Toy – MemSQL

We have a new toy to play with. MemSQL is a “Lock Free”, Just In TIme (GIJ) SQL compler (C++) that is MySQL client compatible. It was developed by two former Facebook developers, Eric Frenkiel and Nikita Shamgunov,  and is said to be the world’s fastest.

I gave it a 30min review.  The install was incredibly simple. I use mysqldump to dump a WordPress tables directly into MemSQL and all when well until I  tried to use the website.  MemSQL is NOT a MySQL drop in replacement. But, they don’t say it is.

MemSQL is ACID compliment and might fit well in a small application needing high read write transactions. (Think stock trading.) There is no descriptions on how to scale.  …

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MySQL Security

A deep dive into the code

MySQL security is like an onion, it has many layers. MySQL check the user source location (IP) and password. MySQL can also check a user’s SSL Certificate credentials. MySQL may or may not give a user access to a set of databases, tables, functions or views based on the user’s Access Control List.

I’ve been reviewing ScaleArc’s iDB for some time.  The use of a proxy complicates the authentication process even more.  This has led to me reviewing all of MySQL Security.  I’ll blog about what I’ve found as I dive into the code.

The Login Handshake

In version 4.0 and before:

  • The server sends a random string to the client, in scramble_buff.
  • The client encrypts the scramble_buff value using the hash of a password that the user has entered. This happens in …
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Percona Tease Kit

Percona you know I love you.  You have the largest brains working with MySQL. Your toolkit (formerly Maatkit and Aspersa) is a real gift to the MySQL community. But stop teasing us with webinars about what it can do and show us how to use it.

The Percona ToolKit needs a cookbook. The documentation is reference only, very thin and total void of useful examples. You’re beginning to frustrate the masses.

Here is what’s happening.  My MySQL server crashes or stalls ever few months.  I searched the Goog and find PT-Stalk :

“watches for a trigger condition to become true, and then collects data to help in diagnosing problems. It is designed to run as a daemon with root privileges, so that you can diagnose intermittent problems that you cannot observe directly. You can also use it to execute a custom command, or to gather the data on demand without …

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The Full Monty – Version 2

Installing MySQL on CentOS 6.2 with PaceMaker, MHA and more

When I work with High Availability software, I’m reminded of the maze in the original computer adventure game “You are Lost in a maze of twisty-turny passages all alike…”.

If you search the web for HA programs you will find many well maintained projects all related that refer each other. The goal of this document is to give you with a step by step guide to a production worthy MySQL system. It should provide at least 99.999% access to your data and be able to scale read requests as you grow.

I have chosen these programs and utilities because they are free (as in beer) and each has enterprise support available. (When you make the money to pay for it.) If you start with this MySQL platform you will avoid many common problems. Just write your application to read and write data from different servers.

Here is what we’ll be …

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I have proof of UFOs

Un-maned Failover Operations

I have video of two MySQL servers (one master, on slave) failing over from Master to Slave.  The Master becomes the Slave and vise-verse with the slave becoming read-only.  Next some load testing and then I’ll post how I did it with FREE software.

Click here to view the video on YouTube.


To NULL or NOT to NULL that is the question.

I liked Shlomi Noach post on “IS TRUE and IS FALSE“.  This kind of logic create bugs.

What will this return?

select if((1 = true) and ( 1 is TRUE) and (NULL is not TRUE), TRUE, FALSE) as answer;

You should know,

NULL is never TRUE or FALSE but


NULL is a little like a vacuum.  Ancient Greek philosophers did not like to admit the existence of a vacuum, asking themselves “how can ‘nothing’ be something?”.    Does GOD exist in NULL?

If  select “” is NOT NULL; is TRUE what is “”?

select "" is NOT NULL;
| "" is NOT NULL |
|              1 |
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The State of High Availability

Searching for the Holly GrailFor months I have been writing and rewriting an blog post called “The Full Monty”. It’s a kind of how to build complete production system from scratch. I’m still not done. Maybe I’m fullish thinking I can build a one type fits all database server. But that’s not the problem. I’ve found myself chasing the Holly Grail of HA and replication.I’ve build many virtual clusters with all the HA / replication package I could find. I’ve tried DRBD, Heartbeat,  Multi Master Management (MMM), Tungsten, …

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