At the MySQL UC 2010 (on Tuesday 4/14 11:55 am) me and my colleague Joffrey Michaie will present MySQL Cluster - Deployment Best Practices. We will give talk about what is important to think about when deploying MySQL Cluster, what to do, what not to do, operational aspects and a few other practical things.
This session will be a great follow-on to the introductory session on MySQL Cluster (and the tutorial).

After the Deployment session, same day at 2:00pm, I will also have a session on …

Q4M (Queue for MySQL) periodically performs an operation called "compaction", which is sort of a garbage collection, that collects empty space from a queue file and returns to the OS.

The pitfall that exists until now was that during compaction, all operation on the queue table was being blocked.

My opinion was (is) that it is not a serious problem for most users, since the time required for compaction will be small in most cases (the time depends on the number (and size) of the rows alive on the queue table, and the number of the rows alive will be mostly small).

But for usecases where fast response is a requirement, I have added a "queue_use_concurrent_compaction" option to Q4M in the 0.9.3 prerelease.  When the variable is set to one in my.cnf, INSERTs will not be blocked during compaction.  Another configuration variable …

Along with maximal possible fsync/sec it is interesting how different software RAID modes affects throughput on FusionIO cards.

In short conclusion, RAID10 modes really disappoint me, the detailed numbers to follow.

To get numbers I run sysbench fileio test with 16KB page size, random read and writes, 1 and 16 threads, O_DIRECT mode.

FusionIO cards are the same as in the previous experiment, as I am running XFS with nobarrier mount options.

OS is CentOS 5.3 with 2.6.18-128.1.10.el5 kernel.

For RAID modes I use:

• single card ( for baseline)
• RAID0 over 2 FusionIO cards
• RAID1 over 2 FusionIO cards
• RAID1 over 2 RAID0 partitions (4 cards in total)
• RAID0 over 2 RAID1 partitions (4 cards in total)
• special …

Berkeley DB (BDB) is undoubtedly the workhorse among the opensource embedded database engines. It started as a university project in the mid-eighties and was further developed by Sleepycat Software, until it got acquired by Oracle in February 2006.

I had the impression that BDB had lost a lot of its popularity among opensource developers to SQLite in recent times, which has evolved into becoming the default choice for developers looking for an embedded data store. I'd assume primarily because the code is not released under any particular license, but put in the public domain …

Dear Community,

It is time to announce the next version of backup software from Percona - XtraBackup 1.1.

The list of changes in version 1.1 includes:
Changelog:

• XtraBackup is built on a base of MySQL 5.1.44 with InnoDB plugin 1.0.6
• Added --host option
• tar4ibd can treat over 64GB file
• tar4ibd is default method for stream, even tar is specified
• the binary supports compressed tables and Baraccuda format

Fixed bugs:

• Bug #529874: innobackupex cannot treat exit code of xtrabackup executable
• Bug #498660: xtrabackup not handling barracuda compressed table format
• …

I got a comment from a reader about the Naive Trees section of my presentation SQL Antipatterns Strike Back. I've given this presentation at the MySQL Conference & Expo in the past.I'd also like to mention that I've developed these ideas into a new book, SQL Antipatterns: Avoiding the Pitfalls of Database Programming. The book is now available in Beta and for pre-order from Pragmatic

The binary version for MySQL Cluster 7.1.2a has now been made available at http://dev.mysql.com/downloads/cluster/ under the Development tab.

Note that this beta load contains the latest NDBINFO and MySQL Cluster Connector for Java (ClusterJ) enhancements – please try them out and provide feedback (any bugs should be reported through bugs.mysql.com.

A description of all of the changes (fixes) that have gone into MySQL Cluster 7.1.2a (compared to 7.1.1) can be found in the MySQL Cluster 7.1.2a Change Log.

Download Tungsten Enterprise v. 1.2.3 (Release date March 16, 2010) This is a maintenance release that adds the following new features plus a number of important fixes: Completely updated documentation, including expanded description on cluster concepts, management procedures, and connectivity options New features for SaaS vendors include transparent session consistency for

A little two-part quiz. If you get the first one without peeking, you're worth your pay as a DBA. If you get the second one without peeking, you may tell your boss that some random guy on the Internet says you deserve a raise.

Start with a text file, 'test.txt', with these three lines:

1
1
2

Set up the test in MySQL:

DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (id int primary key);
LOAD DATA INFILE 'test.txt' INTO TABLE t1;

This gives "ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY'", which is expected.

What's in the table?

Show Answer ▼

It depends. If the engine is MyISAM, then you'll have one row: the first '1' from the file was inserted, everything else was skipped. If the engine is InnoDB, you'll have no rows, because the transaction would rollback. So either 1 row or 0 rows.

…

Brian wrote recently Where did all of the MySQL Developers Go?, while over in Drizzle land they have been accepted for the Google Summer of code along with many other open source projects. MySQL from my observation a noticeable absentee.

Historically, the lack of opportunity to enable community contributions and see them implemented in say under 5 years, has really hurt MySQL in recent times. There is plenty of history here so that’s not worth repeating. The current landscape of patches, forks and custom MySQL binaries for storage engine provider has provided a boom of innovation that sadly is now lost from the core MySQL product.

In Drizzle, community contribution is actively sought and a good portion of committed code is not from the core Drizzle …