If your storage engine returns an error from rnd_init (or doStartTableScan as it’s named in Drizzle) and does not save this error and return it in any subsequent calls to rnd_next, your engine is buggy. Namely it is buggy in that a) an error may not be reported back to the user and b) everything may explode horribly when rnd_next is called after rnd_init returned an error.

Unless it is running on MariaDB 5.2 or (soon, when the patch hits the tree) Drizzle.

Monty (Widenius, not Taylor) wrote a patch for MariaDB based on my bug …

HandlerSocket is cool. But, it turns out there are a few issues.

Justin Swanhart points out HandlerSocket currently lacks atomic operations . Since HandlerSocket uses different connections for reading and writing, you can’t increment/decrement a value without creating a race condition.

Still, the idea of skipping SQL interpretation and just reading the data you know you want is a great one.  Writing data might even be better. But being able to use both SQL and NoSQL could be really wonderful.  What if we could use complex queries to update complex tables and pluck values out as needed.  For example, queries to analyze current weather conditions and produce forecasts that we could then retrieve via a location key? What about updating current condition data …

This document was updated and tested for CentOS 6.0

In my last two posts I installed the HandlerSocket plugin into MariaDB and showed how to use it with Perl.  That’s good, but if you are thinking of using HandlerSocket  I’m guessing you have a very high traffic website and it’s written in PHP.  In this post I’m going to connect HandlerSocket with PHP.  In the next post I’ll discuss using HandlerSocket on a production system.

There are a couple of HandlerSocket php modules projects.  I tried each of them and I found PHP-HandlerSocket was the best.  Both of them are still rough and neither of them have documentation beyond their source code.  Maybe this will move things forward.

Here are the applications you need to have installed that where not installed in my last two posts.  Run this to …

Following the excellent post of Yoshinori about exceeding 750 000 qps with handler_socket,  i was curious to make my own opinion on the state of MySQL and MariaDB regarding simple primary key search.

Quoting  "Most of high scale web applications use MySQL + memcached. Many of them use also NoSQL like TokyoCabinet/Tyrant. In some cases people have dropped MySQL and have shifted to NoSQL. One of the biggest reasons for such a movement is that it is said that NoSQL performs better than MySQL for simple access patterns such as primary key lookups. Most of queries from web applications are simple so this seems like a reasonable decision"

I’m a big fan of NoSQL when it comes to remove useless work put on some …

The title says it all. If you don’t know what HandlerSocket is or why you would want to use it you need to reads Yoshinori Matsunobu’s blog post.

Lets get started.

 login as root

Make sure you have these packages installed:

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

If you haven’t already, install MariaDB and it’s source do that first and make sure it works. Look here http://askmonty.org/wiki/MariaDB:Download#Packages for the packages.

I’m using CentOS 5.5 x64 so I used:

wget http://ftp.osuosl.org/pub/mariadb/mariadb-5.2.4/kvm-rpm-centos5-amd64/rpms/MariaDB-client-5.2.4-94.el5.x86_64.rpm
 wget http://ftp.osuosl.org/pub/mariadb/mariadb-5.2.4/kvm-rpm-centos5-amd64/rpms/MariaDB-server-5.2.4-94.el5.x86_64.rpm …

As you are probably aware, PHP 5.3.4 does not compile with MySQL 5.5 GA. The details can be seen in MySQL bug queue. Basically, the problem boils down to incorrect installation of MySQL headers. MySQL 5.5 build system does not install the headers under the include-prefix/mysql directly but instead installs under the include-prefix directory itself. So, when the PHP build system looks for the MySQL headers, it cannot find <mysql/psi/mysql_thread.h> and so forth.

What is the fix?

The MySQL dev team has committed patches to fix this issue in …

O’Reilly’s 2011 edition of the MySQL conference has an expanded agenda, with good representation from Postgres, CouchDB, MongoDB, and others. Take a look at the full schedule listing, which is being filled out as talks are approved and the speakers verify that they’ll give the session.

I am certainly looking forward to this year’s event. A tremendous amount of progress has landed in GA versions of open-source databases this year. To name just a couple, there’s a new version of Postgres (9.0) with built-in replication and many more improvements; there’s MySQL 5.5 GA; there’s the HandlerSocket NoSQL interface to MySQL; Drizzle has a beta release; and the list goes on. I believe that this conference will have balanced and representative coverage of what’s really important to users. …

My recent account of The State of MySQL forks seems to have gotten quite a lot of attention. I promised to follow up with a separate piece about Drizzle and also PostgreSQL, as the other major open source database, so I'd better keep that promise now.

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Just wanted to highlight that Percona Server has now added HandlerSocket to its most recent release, being the first "MySQL fork/distribution" to ship it in easy to consume binary downloads.

HandlerSocket brings NoSQL to MySQL, and does so with a vengeance! It was developed at DeNa, by Akira Higuchi and is already used in production in their MySQL servers. The announcement on my former collague Yoshinori Matsunobu's blog flaunts a 7x performance improvement over the standard SQL interface in MySQL. The most astonishing part is that their MySQL is now faster than Memcached, even if the latter doesn't store anything to disk, so with this NoSQL-for-MySQL solution it makes sense to remove the caching layer completely! …

Over the last few months I have been pleasantly surprised by the number of people using open source builds of Tungsten.  My company, Continuent, has therefore started to offer support for open source users and will likely expand these services to meet demand.

There have also been a number of requests to add specific features to open source builds, especially for replication. We have added a few already but are now considering pushing even more features into open source if we can find sponsors.  These add to a number of great features already in open source like global transaction IDs, MySQL 5.0/5.1, basic drizzle replication, transaction filtering, and many others. 

Do you have special replication or clustering features you would like to see added to Tungsten? Specialized MySQL to PostgreSQL replication?  Management and monitoring commands?  Cool parallel replication problems?  …