There is a little-known setting, myisam_block_size in MySQL. This affects the block size used in the indexes of MyISAM tables stored in .MYI files on disc and in the key buffer.

The default value is 1k, this is possibly too small for best performance on modern systems; in particular, many filesystems used a bigger block size, so writing a single index block requires a read followed by a write. Random reads are really slow on hard discs (writes are mostly fast as they go into your battery-backed raid controller which has lots of RAM).

I am currently in the process of experimenting with myisam_block_size, and so far have determined the following:

• myisam_block_size is settable only at server start time, either in my.cnf or on the command-line
• myisam_block_size only affects newly created tables or tables rebuilt using ALTER TABLE; existing MyISAM tables keep their old index block size and …

In record time, less than a week after the conference (thanks to the free Pinnacle Video Spin and YouTube), all 11 videos that were taken at OpenSQLCamp Europe are online.

For those who missed the sessions, or just want to relive the fun!

Almost all the sessions were filmed; regrettably Darren Cassar’s Securich – MySQL user administration and security made easy! and Stephane Combaudon’s Minimizing data access with covering indexes were not.

The YouTube videos have the descriptions and resources from the official conference pages, and links to pages. If there is more information to add (for example, the slides from a talk are now online), or if …

Over the last month I have been working on a ZFS Tuning for Databases presentation. I'll be presenting it live tomorrow 8/26/09 at 8 AM PST.

This based on a lot of work done at Sun as well as in the community. With the massive adoption of Solid State Devices (SSDs) (thank you iPOD) the storage market just got a whole lot more interesting. Incorporating SSDs into a ZFS pool is a breeze. This presentation is meant to help you get the best out of the ZFS + SSD combination for databases. We look into Postgres, MySQL and Oracle. I also provide a quick into into Sun's unified storage 7000 series systems.

If you are interested do Register Now

One of the things that repeatedly seem to puzzle users about the DRBD is the question of whether to use internal or external metadata. Remember, DRBD sets aside a small area on a local disk (on every cluster node) where it keeps the Activity Log, the quick-sync bitmap, data generation UUIDs, and a few other bits and pieces for local housekeeping.

The specific aspect that is to be discussed here is the Activity Log. Without going into too much detail, let’s be satisfied with the factoid that DRBD …

This time, I’m talking about indexes for string typed columns. In particular, I’ll show a procedure I find useful while looking for good index length values for these columns. I’ll use a sample table called people. Here’s what it looks like: mysql> desc people; +————+——————+——+—–+———+—————-+ | Field | Type | Null | Key | Default … Continue reading Indexing text columns in MySQL →

Related posts:

1. Using MySQL Proxy to benchmark query performance By transparently sitting between client and server on each request,...
2. Making use of …

Today, the InnoDB team announced the latest release of the InnoDB Plugin, release 1.0.4. Some of the performance gains in this release are quite remarkable!

As noted in the announcement, this release contains contributions from Sun Microsystems, Google and Percona, Inc., for which we are very appreciative. This page briefly describes each of the contributions and the way we treated them. The purpose of this post is to describe the general approach the InnoDB team takes toward third party contributions.

In principle, we appreciate third party contributions. However, we simply don’t have the resources to seriously evaluate every change that someone proposes, but when we do undertake to evaluate a patch, …

In our last post, Bradley described how auto increment works in TokuDB. In this post, I explain one of our implementation’s big benefits, the ability to combine better primary keys with clustered primary keys.

In working with customers, the following scenario has come up frequently. The user has data that is streamed into the table, in order of time. The table will have a primary key that is an auto increment field, ‘id’, and then have an index on the field ‘time’. The queries the user does are all on some range of time (e.g. select sum(clicks) from foo where time > date ‘2008-12-19’ and time < date '2008-14-20';).

For storage engines with clustered primary keys (such as TokuDB and InnoDB), having such a schema hurts query performance. Queries do a range query on a secondary index (time), and then perform point …

Eric Day and Patrick Galbraith spoke on Drizzle, Gearman and Narada at the July 2009 Boston MySQL User Group. This is part 1 of the video, which is about an hour long and is about Drizzle.

"We will explain what the Drizzle project is, what we aim to accomplish, and an overview of where we are at."

The slides can be downloaded from http://www.oddments.org/notes/DrizzleGearmanBoston2009.pdf

The User Group calendar item for this event is http://www.meetup.com/mysqlbos/calendar/10607736/

read more

It’s been just over three months since the April 2009 MySQL Users Conference and Expo. It took a while for the files to be processed, and then uploaded to www.technocation.org, and then I found out that the online streaming was not working properly. So I started playing with things, re-encoding some videos, updating the software, but to no avail.

Just as I was about to give up I got notification that Technocation, Inc. was accepted into YouTube’s not-for-profit program, which allows movies larger than 10 minutes to be uploaded and viewed advertisement-free.

So then I had to upload the videos to YouTube and add descriptions.

So with no *further* delay, here are all the videos from the 2009 MySQL Conference and 2009 MySQL Camp:

The brief description — just the playlists:
Conference …

Do you need to find qps for peak hours not avg qps through mysql life.

The MySQL 5.1 offers new GLOBAL_STATUS information schema tables. These can be used to report certain performance metrics, such as the number of queries processed per certain seconds, NOT overall avg queries per second, Its good to know how much qps in peak hours.

http://forge.mysql.com/tools/tool.php?id=217