The MySQL 5.1 DBA exam is in alpha-test right now and some of the reviewers have had questions about upgrade exams. The new exams are no longer multiple choice. They are based on a candidates performance with a real database on a virtual server.
In the past I have stated that there was not going to be an upgrade exam. This was due to the change in exam format and the history of previous upgrades not being popular. Less than forty folks took the Core to Dev upgrade exam (about 5% with that certification) and the numbers are worse for the Pro to DBA upgrade. Why spend time on something that is not going to be cost justifiable?

But my reviewers are trying to convince me to have an upgrade. It would not be that much more work to offer a hands that could be taken over the Internet. You …

Vadim announced Percona's XtraDB a couple of days ago, and then followed up with some really fun benchmarks. Of course, the first thought I had was "I need another cup of coffee," which was shortly followed by "I should merge that in to Drizzle!"

First step was merging it in to a branch of the innodb-plugin-upstream branch, making an

lp:~mordred/drizzle/xtradb-upstream

Merged it up to drizzle trunk, and now we have:

lp:~mordred/drizzle/xtradb

But what I really want is for our changes to InnoDB/XtraDB to get merged in. So I also make a branch of XtraDB and applied our stuff to it:

lp:~mordred/percona-xtradb/drizzle

My goal …

A number of commenters on my previous entry thought I was basically saying "Screw Windows". Lukas Smith and Bill Karwin, both of whom I respect enormously, noted that Windows is a dominant development platform for MySQL users, and that one of the reasons for MySQL's popularity was that it runs smoothly (for a while now) on Windows.

Bill and Lukas: You are 100% correct.

That said, what I wrote was this:

Forget Windows for now: Use open source, community-maintained, and standardized libraries within the kernel. Don't rewrite libc and various other quality open source libraries because of Not Invented Here syndrome or because Windows lacks these things. Focus on the standards and don't bother with platforms that don't conform to POSIX. If Microsoft wants future MySQL versions to run on its platforms, partner with Microsoft …

Cloud computing has been getting lots of buzz over the last few years, and it only seems fair that we talk a little bit about where a Waffle Grid can fit in the cloud. One of our key visions for Waffle Grid is to enable people to add capacity & resources on demand ( as needed ) as load and demand increases without rearchitecting the environment or the application. As I showed previously given the right setup ( disk bound workload, fast interconnect ) Waffle Grid can yield substantial performance benefits. This offers a compelling offering for cloud computing environments.Let’s use a simple example for those that may not fully understand the benefits of cloud computing. Being Christmas time, if you run a ecommerce site that is blessed with increased sales this time of year you probably know that your web infrastructure can sometimes become strained during this time of year. In the past many companies have built their infrastructure to handle this …

I was surprised by even the gap I saw on Vadim's post on the improvements of using the Noop IO scheduler. I've been changing my thoughts on what to set the scheduler to lately, and it's all leaning to Noop as the default.

An explanation first:
IO Schedulers (aka elevators) are a method of trying to get the best possible performance out of your disk subsystem as possible. Since your disk is essentially a mechanical device - it has a difference in performance between whether or not you are performing actions sequentially - or when you are performing actions randomly. And this difference can be huge! Last time I tested, a typical 7200RPM consumer hard drive could write 60MB/s sequentially, but performance dropped to only a few MB/s when I started trying to write small pieces of random data.

So how do …

I was surprised by even the gap I saw on Vadim's post on the improvements of using the Noop IO scheduler. I've been changing my thoughts on what to set the scheduler to lately, and it's all leaning to Noop as the default.

An explanation first:
IO Schedulers (aka elevators) are a method of trying to get the best possible performance out of your disk subsystem as possible. Since your disk is essentially a mechanical device - it has a difference in performance between whether or not you are performing actions sequentially - or when you are performing actions randomly. And this difference can be huge! Last time I tested, a typical 7200RPM consumer hard drive could write 60MB/s sequentially, but performance dropped to only a few MB/s when I started trying to write small pieces of random data.

So how do …

With all the booha about MySQL not being ready for GA, it makes me almost afraid to announce, ahem, ... and PBXT is, ehr, RC.

It has been just over a year now since I started developing the fully durable version of PBXT. Before that, PBXT was Beta. After that, it was Alpha again.

Now we have 2 solid Beta versions behind us, Vladimir and I have fixed all known bugs for this version, including quite a number of foreign key bugs. We have all 259 mysql-test-run tests that were adapted for PBXT (and a bunch of our own) running through without any errors on 4 platforms: Mac OS X, Linux 32-bit and 64-bit, and Windows. Our buildbot is giving us a green light, at last!

Besides this we have done crash tests, load tests and crash and load tests (I mean recovery)! And maybe most important, we have it ticking away in a very demanding OEM product …

If you are using MySQL with the InnoDB Storage Engine, you know and probably use FOREIGN KEYs. There are some who dislikes the use of these, saying the are bad for performance, but I tend to disagree, if the price of keeping my data consistent is a slight performance degradation, then so be it.

Anyway, I was going to write about a couple of lesser known FOREIGN KEY constraint attributes here. We all know what a FOREIGN KEY constraint is, right? A reference from a column or set of columns in one table to the PRIMARY KEY in another table? Yes, this is correct, but it's not the whole truth, actually, a FOREIGN KEY is a reference to a PRIMARY KEY or UNIQUE key in another table. Being able to reference a UNIQUE constraint is sometimes rather useful.

But before we go into that, lets look at a few subtle differences between a PRIMARY KEY and a UNIQUE constraint. In RDBMS design lingo, the UNIQUE constraing usually represents a …

Features:
* The ‘query sniffer’ can now connect to and retrieve data from a running instance of the MySQL-proxy program used by one or more clients to connect to MySQL.  A LUA script for controlling the proxy for use with MONyog is provided with this build.  With this sniffer option the SHOW FULL PROCESSLIST statement will not be sent and thus use of ‘query sniffer’ will not put any load on MySQL.
* SSH connections will now attempt more authentication methods in case the first method attempted failed.  This will solve problems reported with tunneling to MySQL on FreeBSD that as per default does not support the full range of SSH authentication methods (and possible similar problems).

Downloads: http://webyog.com/en/downloads.php
Purchase: …

I guess it is first reaction on new storage engine - show me benefits. So there is benchmark I made on one our servers. It is Dell 2950 with 8CPU cores and RAID10 on 6 disks with BBU, and 32GB RAM on board with CentOS 5.2 as OS. This is quite typical server we recommend to run MySQL on. What is important I used Noop IO scheduler, instead of default CFQ. Disclaimer: Please note you may not get similar benefits on less powerful servers, as most important fixes in XtraDB are related to multi-core and multi-disks utilization. Also results may be different if load is CPU bound.

I compared MySQL 5.1.30 trees - MySQL 5.1.30 with standard InnoDB, MySQL 5.1.30 with InnoDB-plugin-1.0.2 and MySQL 5.1.30 with XtraDB (all plugins statically compiled in MySQL)

For benchmarks I used scripts that emulate TPCC load and datasize 40W (about 4GB in size), 20 client connections. Please note I used …