Thu, 2013-04-25 11:37 About the Author Sysbench OLTP, transactions per second

When dealing with high performance, low latency storage devices, such as SSD cards, one finds bottlenecks in new places. This is a story about such a bottle neck and how to work around it.

One unique feature of InnoDB is the double write buffer. This buffer was implemented to recover from half-written pages. This can happen in case of a power failure while InnoDB is writing a page (16KB = 32 sectors) to disk. On reading that page, InnoDB would be able to discover the corruption from the mismatch of the page checksum. However in order to recover, an intact copy of the page would be needed.

The double write buffer provides such a copy. Whenever InnoDB flushes a page to disk, it is first written to the double write buffer. Only when the buffer is safely flushed to disk, InnoDB writes the page to the final destination. When recovering, InnoDB scans …

I've just created a release of Libdrizzle 5.1.4 (the BSD licensed C connector for MySQL servers) which for me is one of the most exciting releases to date.

Why?
Not because the amount of features or anything that we have added, in fact this is mostly a minor release with bug fixes.  It is because Brian Aker and I didn't submit the most code for it.  That honour goes to Wim Lewis from The Omni Group who has done a fantastic job fixing up Libdrizzle.

As for the release itself the main fixes revolve around cleaning up code and many fixes to the server-side prepared statement handling.  Behind the scenes Wim has supplied many improvements to the test suite and Brian has setup more platforms to test against in Jenkins.  …

After nearly every recovery case the same question arises: How many MySQL records were recovered and how many were lost.

Until now there was no way to answer the question without manual investigation. As it turned out a small change can make a big difference.

There are two ways to know how many records an InnoDB page stores. The index page has a header PAGE_N_RECS – this is a number of records the page stores. Obviously it doesn’t count any deleted records. The second method to confirm how many records are in the page is to follow records pointers – and count them.

As you might know, records inside an InnoDB page are organized in an unidirectional list. The list is sorted by primary key and starts with the internal record infinum and ends with another internal record supremum. If you …

MySQL Community Awards 2013 were announced earlier today at the MySQL Conference & Expo...

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It's time again to award persons, applications and companies in the MySQL Community. This is an annual tradition to highlight and give appreciation to some of the things that make MySQL so great.

The first awards were given out in 2005, and since 2010 the winners have been chosen by a community panel of which myself and Shlomi Noach are the co-secretaries. There has been a public nomination period in January and the final voting is done by a panel who are themselves former winners of the award.

The first category is

MySQL Community Awards: Community Contributor of the Year 2013

The first winner is...

Jeremy Cole

read more

Thanks to all of those who came to the lightning talks this evening. We’ve got the audio posted here and the lyrics below.

A special thanks to Erin Grace O’Malley O’Neill for the great performance. Thanks also to @NuoDB and @geobdz (whose photo is below) for tweets.

Stay tuned for the video as well….

MySQL Paradise

As I browse through the archive where I keep all my code
I look at my software and see it’s very old
But that’s just perfect for a …

The MariaDB project is pleased to announce the immediate availability of MariaDB 10.0.2. This is an alpha release. See the release notes and changelog for details.

Download MariaDB 10.0.2

Release Notes  Changelog  Overview of 10.0

APT and YUM Repository Configuration …

We want to thank everyone for naming Continuent the Corporate Contributor of the Year 2013 for ongoing contribution to the MySQL community, at Percona Live MySQL Conference & Expo 2013. The MySQL Community Awards are given annually to the people and companies that support the MySQL ecosystem. 

The MySQL Community Award for Corporate Contributor of the Year recognizes a company or other

Yes, Percona Live ends on Thursday, but on friday. at the same location, there is SkySQL Solutions day. Attendance is free, and among the highlights yours truly will be speaking! Register here for this free event: http://info.skysql.com/roadshow2013-0 Another highlight of this is that it ends with a Biergarten. Free!

/Karlsson

Years ago I complained bitterly about MySQL’s backwards development and release model, which made guinea pigs out of the paying customers. I think I’d be remiss if I didn’t say it’s been fixed for years. And it’s really fixed right in my opinion – much better than what I proposed. Congratulations, and thanks, to the MySQL team for superhuman software engineering, release engineering, documentation, bug triage and analysis, and doing a million things right – in other words, making a damn good database, which is hard.

MySQL Connector/J provides loadbalancing and failover support.  While testing failover I wanted to know what was happening under the hood. Specifically I wanted to know when a host was blacklisted and which host.

If you set loadBalanceStrategy to random in your connection properties, which has been the recommended strategy over round-robin, you can modify the RandomBalanceStrategy.java file to log when a host is blacklisted.

Using guidance found on Todd Farmer's blog (http://mysqlblog.fivefarmers.com/) and a bit of twiddling it wasn't difficult.

In my setup, I have jboss-as-7.1.1. running on my local windows machine with my test app I developed using one of the JBoss quickstarts.

The connector (connector-java-5.1.21) is deployed and I have the source on C:\mysql-connector-java-5.1.21.

In …