A while back I looked at the Memcached UDF for MySQL, and noticed that it didn't use libmemcached in an optimal way. In order to work in a multithreaded environment it used the following pattern:

   memcached_st* clone = memcached_clone(NULL, memc);

   ... memcached operations using the clone ---   

   memcached_free(clone);

Well, that doesn't look bad, does it? Well, it isn't that bad, but if you look at the network traffic you will see that we end up connecting / disconnecting to the involved memcached servers every time, and memcached is not optimized for "single-shot" connections.

So how should you solve this? Well, you should reuse your clones! And luckily for you, you don't have to reinvent the wheel. Yesterday I pushed a patch to libmemcached introducing a new library: libmemcachedutil. The intention of that library is to put utility functions built on top of libmemcached …

I’ve decided to start a series of blog entries on not-so-obvious findings that I’ve found while working on my new project. By archiving the findings, I’m hoping that I can help those that are looking into developing a storage engine for the MySQL family in the future.

Accumulating these mini-knowledge would also be useful for me since I can refer back to it when I forget something. Also, once I write enough entries I’m planning on summarizing them and making it available on the Drizzle Wiki. If MySQL is interested in updating the engine documentation, I would be more than happy to help there too.

So to begin with, I’ll describe something trivial that I stumbled across while trying to catch an error on duplicate primary key insertion to the data table.

Here are my new db_STRESS results obtained on the latest Sun M5000 server (SPARC64-VII 8CPU quad-core / bi-thread 2400Mhz). I was very curious to retest the "official" MySQL 5.4 on this machine as well other versions and InnoDB engines. But on the same time the new XtraDB version 5 was announced. As well Google shipped their v3 patch. How to resist? :-) (I'll try to be short :-))

MySQL 5.0 & 5.1

There is no more performance gap between 5.0 and 5.1 as I observed before , both versions are having near the same performance and both are way slower comparing to others :-) So, honestly, if you have any performance problem - why do not migrate to 5.4, XtraDB, or at least the latest InnoDB plugin?..

XtraDB Performance Improvements

I was very pleasantly surprised by performance improvements done in XtraDB-5! It's …

I’m surprised I haven’t used it before. I do have to say that MySQL Sandbox is incredibly awesome. In this case, it saved me waiting for a compile of MySQL 6.0, which is always a good thing.

The goals of the project are basically

• Modularity. Make it easier to add new features without breaking existing ones.
• Pluggability. Make it easier for third parties to add functionality.
• …

The goals of the project are basically

• Modularity. Make it easier to add new features without breaking existing ones.
• Pluggability. Make it easier for third parties to add functionality.
• …

While preparing the slides, I realized that, for the first time, we have a product that allows a painless performance gain. Unlike all the tuning and technological improvements that you can use to improve …

I recently did a disk bound DBT-2 benchmarking on SSD/HDD (MySQL 5.4.0, InnoDB). Now I'm pretty confident that storing tables on SSD, redo/Binlog/SYSTEM-tablespace on HDD will be one of the best practices for the time being.

This post is a detailed benchmarking report.
(This post is very long and focusing on InnoDB only. If you are familiar with HDD/SSD/InnoDB architecture and understand what my blog title means, skipping section 1 (general theory) then reading from section 2 (benchmarking results) would be fine. )

1. General Theory of HDD, SSD and InnoDB

SSD is often called as a disruptive storage technology. Currently storage capacity is much smaller and unit price is much higher than HDD, but the situation is very rapidly changing. In the near future many people will use SSD instead of HDD.

From DBA's standpoint, you have a couple of choices for storage allocation.
- …

Scaling MySQL and ZFS on T5440

Solid State Disks : a 2009 fashion

This technology is not new : it originates in 1874 when a German physicist named Karl Braun (pictured above) discovered that he could rectify alternating current with a point-contact semiconductor. Three years later, he had built the first CRT oscilloscope and four years later, he had built the first prototype of a Cat's whisker diode, later optimized by G. Marconi and G. Pickard. In 1909, K. Braun shared the Nobel Prize for physics with G. Marconi.

The Cat's whisker diodes are considered the first solid …

Boost is a cross-platform library, which partly is just source code (templates) and partly libraries, for C++ development. Many big projects use Boost. OpenOffice.org is one of them. Parts of Boost are part of TR1 (Technical Report 1), which is pre-C++ 0x. We started with exchanging std::auto_ptr usage with boost::scoped_ptr. We will continue with scoped_ptr and shared_ptr in few places, where we had home-grown solution for now, so we will standardise.

In addition, we are looking at boost::date_time and the boost::thread. Currently Date(Time) data is being passed to the connector using strings and we would like to use format that is better and we believe that Boost has good library for that. As Boost usage is wide we think we can enforce its usage.

We will add thread-safety, and …