I recently encountered an error when two slave databases were using the same server_id value. I know having unique server_ids across all MySQL databases in a given replication topology is a best practice, but I'm not sure I understand exactly why MySQL is trying to enforce uniqueness in this specific case.

The most obvious reason to use unique server_id values for every database in a replication setup is to avoid having a master and slave with the same server_id. If that happens the slave will skip any events coming from that master.

But if I have two slaves with the same server_id, that should be safe unless I promote one of those slave to be the master of the other. Is that the case that MySQL is trying to protect me from, or is there some other case I am missing?

My specific problem started when I cloned a slave database. This is something I do fairly often, but most of the time I am creating a new read slave, and I …

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This 3 day instructor-led class provides you a full understanding of cluster concepts as they relate to MySQL Cluster  as well as how to properly configure and manage the cluster nodes to ensure high availability, how to install the different nodes and provide a better understanding of the internals of the cluster.

Here are some of the events already on the schedule for this course:

Last week I wrote about our participation in the SkySQL and MariaDB roadshow. First event in Stuttgart completed on Friday, and the tour continues into Hamburg this Friday and Stockholm on February 7th.

But we will also be busy speaking at some other conferences this Spring.

Fosdem, Brussels. February 2-3.

Next weekend we will be in the MySQL and Friends dev-room at Fosdem. Henrik will be giving the Introduction to Galera talk.

Fosdem is …

The next Helsinki MySQL User Group is set for Tuesday, February 19. Lari Pulkkinen from Arbitron Mobile will talk about their project adopting SSD disks for better MySQL performance. Yes, there are benchmarks included.

Note the changed location: Oracle office in Gräsantörmä 2, Espoo. We are glad to have Oracle Finland sponsoring the user group by taking turns as meetup host. Food and sauna will be available after the talk as is customary.

More details and signup at Meetup.com.

This article was initially planned to follow the previous posts about RW (Read+Write) workloads on MySQL & Linux (part#1, part#2)... But, when I've started to run real MySQL/InnoDB IO-bound tests on the Fusion-io card, I've quickly realized that I'm hitting so hot internal contentions within InnoDB code, that I'm simply unable to use storage capacity on its full power.. So, I've moved to another server (having SSD only), and then continued with it (as to explain RW limits it'll be pretty enough). Also, curiously, on this server XFS performance on writes is way better than EXT4 (while on the the previous server XFS got some unexpected problems, seems to be known bugs)..

So far, for the …

I wrote pt-archiver for jobs like deleting or archiving rows from a big table in small chunks. These days, that’s the kind of task I like doing inside the database, and Shlomi’s magical common_schema feels a lot more suited for this than an external Perl script. When I say it’s magical, it really does feel magical. It’s amazing how he’s created an entire expressive scripting language that runs in MySQL and feels just right for the job.

Preparing for my talk for Percona MySQL University in Raleigh,NC, Tuesday 29th of January I have created the outline of improvements available in MySQL 5.6 which I thought was worth sharing to give a feel for how massive work have been done for this release in variety of areas. I’m sure the list is not complete so If I miss something significant please let me know through the comment and I’ll update the page

Scalability
- Scalable Read Only Transactions
- Concurrent Innodb data file extension
- Non-Recursive Deadlock Detection
- Faster Locking Primitives
- Improved Innodb Thread Concurrency
- Multiple background Purge Threads
- Improved Purge lag control (now works)
- Split of “Kernel Mutex”
- Data Dictionary Cache
- Improved Adaptive Flushing
- Page …

This week we discuss part 1 of the new optimizer enhancements in MySQL 5.6. Ear Candy is a gotcha about persistent replication configuration, and At the Movies is MVCC in PostgreSQL.

Events

Galera, SkySQL and MariaDB are doing a Road Show in Hamburg on February 1st and Stockholm on February 7th.

FOSDEM 2013 is taking place in Brussels, Belgium Sat Feb 2 - Sun Feb 3rd.

OSCON 2013 will take place in Portland, OR from Monday July 22nd through Friday July 26th. The call for speakers closes at midnight Pacific Time on Monday, February 4th.

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I promised to write this blog post long time ago at one of conferences in Russia. Don't know why I delayed this, but finally I did.

We, members of MySQL bugs verification group, have to verify bugs in all currently supported versions. We use not only version reported, but test in development source tree for each of supported major versions and identify recent regressions.

You can imagine that even if I would do so for simple bug report about wrong results with perfect test case, which requires me simply run few queries I would have to start 4 or more MySQL servers: one for each of currently supported versions 5.0, 5.1, 5.5 plus one for current development. And unknown number of servers if I could not repeat or if I want to check if this is regression.

Even if I have all these basic 4 servers running I still should type all these queries at least 4 times. How much time it would take to verify single bug …

February is turning out to be a busy month. I’ll be giving a talk about MariaDB at the SkySQL Solutions Day in Hamburg, alongside Sergei Golubchik. This happens February 1 2013.

I’ll also be in Brussels for FOSDEM and presenting at the MySQL & Friends devroom. Here I will talk about MHA and how you can get automated MySQL failover. I’ll also be hanging out at the CentOS booth with Karanbir Singh giving away MariaDB stickers all weekend. If you’re at FOSDEM, don’t forget to sign up for the …