This article contains my notes and detailed instructions on setting up a MySQL cluster. After reading it, you should have a good understanding of what a MySQL cluster is capable of, how and why it works, and how to set one of these bad boys up. Note that I'm primarily a developer, with an interest in systems administration but I think that every developer should be able to understand and set up a MySQL cluster, at least to make the dev environment more robust.

Notes

• High availability. If one or some of the machines go down, the cluster will stay up, as long as there is at least one copy of all data still present. The more redundant copies of data there are, the more machines you can afford to lose.
• Scalability. Distributed architecture allows for load balancing. If your MySQL …

Today sees the release of our latest CAOS report, Turning the Tables? ? The impact of open source on the enterprise database market, which examines - as the subtitle suggests, how much of an impact the open source database projects and vendors have made on the traditional relational database market.

One of the key findings is that open source software has had a superficial impact on the enterprise database market in that adoption has been widespread but shallow. While open source databases have been widely deployed for Web-tier applications, there has been minimal adoption in the enterprise application tier, and adoption for enterprise applications is at this time limited to certain specific application workloads.

Some people may be inclined to disagree with that assessment, but you only have to look at the comparative revenues of the open …

On several occasions this year I’ve been prompted to mention in conversation Ingres as an alternative Open Source Database. Jonathan Levin in A list of Open-Source Alternatives to Business Applications was the latest example where Ingres was not mentioned and perhaps it should have been.

Want features like online backup, online alter, multi-master replication, parallel queries and partitioning. These are all long existing features in a more mature product then MySQL presently. Is this a sleeping giant that nobody remembers about? Ingres has been around a long time, in fact my experience extends back to 1988 (that’s 20 years).

From a product perspective they have created a number of pre-packaged product stacks, for example …

While doing a standard audit for a new client, I recommended a few changes to get better performance. Because I had several changes, I used the documentation at

http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html

and found that innodb_flush_log_at_trx_commit is a dynamic variable. I was surprised, because most operations dealing with file sizes and operations are not dynamic. But the client proceeded with:

set global innodb_flush_log_at_trx_commit = 2;

and got:

ERROR 1193 (HY000): Unknown system variable 'innodb_flush_log_at_trx_commit'

So I searched for others who may have had the same error, and ended up getting an unintentional googlewhack. Well, it’s not a real Googlewhack, because it has more than 2 …

After following the scale up path (i.e. buy bigger boxes) for a while now, we definitely need to scale out as things start to become “unhandy” and simply HUGE. (See small things are better)

We are running an OLTP application with about 200 million transaction per month. Currently we have some very large tables with more than 1,5 billion rows and the total database size is about 600 GB - all InnoDB.

What we want to implement is application based sharding, i.e. splitting up the big tables and distribute them among many smaller servers. Furthermore we need to implement some sort of archiving mechanism since the db size is growing very fast. Putting old data into compressed myisam tables seems to be a good solution here.

So, how to implement this?

These solutions come into mind immediately:

…

I’m still looking for new entries. I get quite a few suggestions, but not all of them make it into quiz questions. Do send in your suggestions!

This entry comes from Rudy Limeback

A user searching your website is moving through categories, and you want to display descriptions of these categories as the user progresses. Your basic SELECT looks like this:

SELECT id, description
FROM descriptions
WHERE id IN (23, 6, 9, 37)

You want the descriptions (records) to appear in the same order as the IDs listed in the WHERE clause.

How do you do that?

Show answer

Answer: Tag on an ORDER BY clause with the FIELD function like the following:

ORDER BY FIELD(id, 23, 6, 9, 37)

Very handy. I only wish Rudy had told me this 6 months ago when I was trying to do something exactly …

Reading Martens interview we see the quite:

"As soon as the deal closed we immediately secured a big deal with a major European national police agency," said Mickos, now SVP database products at Sun. "Key to them choosing MySQL was that we are now part of a much larger public corporation. The deal wouldn't have happened when we were private."

Cool stuff! But I'm wondering how much the opposite applies as well - this would leave small companies to seek for other ways to get the service they need ?

As company gets ready to server higher end customers it often "moves up the stack" and fails to deal with needs of lower end customers. This especially applies to Professional Service Companies.

Let me give you an …

Returning an error message is one of the tasks that may become common when working with MySQL Proxy.
Let's say that you want to prevent users from querying your database at a given time. The most sensible answer that you would send to the client that is requesting a query in the forbidden period is an error message. Not only that, the client must receive an error code and SQL state, as if the error were issued by the database server.
With MySQL Proxy, an error set is a legitimate packet to be sent back to the client, and thus you can return a customized error in answer to any query.

function error_result (msg, code,state)
  proxy.response = {
      type        = proxy.MYSQLD_PACKET_ERR,
      errmsg      = msg,
      errcode     = code,
      sqlstate    = state,
  } 
  return proxy.PROXY_SEND_RESULT
end …

Well, as most of you may know, Google Summer of Code is nearing and I have seen many
MySQL blogs urging people to contribute ideas or mentor projects.


My Idea
So I'm going to suggest an idea and as the title already mentions, I think it would be a good idea to add some new Datatypes. Specifically, a new Email datatype.

Now I already hear you saying "Email is a string, why would you need a datatype for it?", but hear me out.

So basically, I personally, have been dealing a lot with trying to clean email addresses and customer data so that my company can help their biggest client use this data in their new CRM system.

I thought it would have been a good idea to implement an email datatype inside MySQL that already has the standard regex for emails and has a defined varchar for the standard …

MySQL Workbench, the successor to DBDesigner 4 from FabForce, is a visual database design tool that integrates database design, modeling, creation and maintenance into a single, seamless environment for the MySQL database system. You can use it to design and create new database schemas, document existing databases and even perform complex migrations to MySQL.

It’s now a good week ago since our first Release Candidate numbered 5.0.15, and if you haven’t checked it out yet, now is a good time!

References:

• Wikipedia: http://en.wikipedia.org/wiki/MySQL_Workbench
• MySQL Forge: …