We all know disk based temporary tables are bad and you should try to have implicit temporary tables created in memory where possible, do to it you should increase tmp_table_size to appropriate value and avoid using blob/text columns which force table creation on the disk because MEMORY storage engine does not support them Right ?

Wrong.

In fact setting tmp_table_size is not enough as MySQL also looks at max_heap_table_size variable and uses lower value as a limit to for in memory temporary table after which it will be converted to MyISAM.

To make things more confusing this is not what you would read in MySQL manual as far as I understand it:
From http://dev.mysql.com/doc/refman/5.0/en/memory-storage-engine.html

MEMORY table contents are stored in memory, which is a property that MEMORY tables share with internal tables that the server …

Welcome to the 28th edition of Log Buffer, the weekly review of database blogs. It was a busy week in the blogs, but then, it always is. Let’s start with some open source software (OSS) items. Stephen Walli published two far-looking “thought experiments” on Once More unto The Breach. In the first, entitled Microsoft and [...]

So, a little gotcha:

The CHAR() and VARCHAR() types are different types. MySQL silently converts any CHAR() fields to VARCHAR() when creating a table with at least 1 VARCHAR() field.

http://dev.mysql.com/doc/refman/5.0/en/silent-column-changes.html

If any column in a table has a variable length, the entire row becomes variable-length as a result. Therefore, if a table contains any variable-length columns (VARCHAR, TEXT, or BLOB), all CHAR columns longer than three characters are changed to VARCHAR columns. This does not affect how you use the columns in any way; in MySQL, VARCHAR is just a different way to store characters. MySQL performs this conversion because it saves space and makes table operations faster.

However, that’s not entirely accurate. Because according to the manual page at …

Download the video at:

http://technocation.org/videos/BostonMySQLJanUserGroupBrianAkerLg.wmv
- 520 kbps, 320 x 240, 354M. Small size, low quality, but you can still see the slides and hear everything.

http://technocation.org/videos/BostonMySQLJanUserGroupBrianAkerSm.wmv - 45 kbps, 320 x 120, 29M. Small size, low quality, but you can still see the slides and hear everything.

Technocation, Inc. received a donation of a Sony Handycam DCR SR80 (http://tinyurl.com/yvyfam ), extra-long battery, microphone (proprietary Sony that goes with the camera).

In a short sentence: I am impressed. The sound …

A while ago when I started my first job in LA, I was using MSSQL. I was told to never use count(*), and rather to use count(1). Several people insisted this performs better than count(*), and since I really didn’t care to argue or look into it, I just started doing it.

Fast forward to today, where I am still writing count(1), but on MySQL. I’m at a different company now, but working with a lot of the same people. The person who used to be my boss is now my equal, and while mytop was running, noticed the count(1) and was happy to see it. Which reminded me to wonder - does it even matter?

(Using a table called questions, 130K rows)

EXPLAIN SELECT count( 1 )
FROM questions;

Says it’s a simple select, and it’s using the index. Fantastic.


explain select count(*) from questions;


Same result as above. I’ve always assumed that the database …

There's a thought provoking article by open source guru Bernard Golden over at the CIO blog web site called "Why CIOs Don't Care About Open Source."  The title alone is enough to give me pause; and sometimes that's the key to a good article.  Get people to stop and think about an issue and start a dialog.  Golden identifies some of the reasons why large companies might not see open source is strategic: it's low dollar amount, it's not "analyst approved" or the IT department is busy maintaining and optimizing the last generation of software rather than looking forward to the next. 

While these are no doubt valid observations of many overworked CIOs, I think likely is not the case among more innovative companies.  We've sold a lot of MySQL to companies where the CIOs have established an open …

I've already sent out the invitation and announcements to various channels, but let me repeat it once more: the 5th Hamburg MySQL User Group Meetup is coming up on Monday, 5th of Februrary. So far, 15 people have already RSVPed, so it's going to be a fun evening again. If you have not done so yet, please register via meetup.com or Xing soon! I will give a 15 minute lightning talk about "What's new at MySQL AB", but we're still looking for another MySQL-related talk. If you want to share your experiences with MySQL or talk about a certain application or tool that has a relation to MySQL, please let me know! As usual, we'll meet a 19:00 at the Chinese Restaurant "Ni Hao", …

It looks like it looks like there are going a lot of discussions about future of MySQL Community Binaries, see for example this post and Kaj's clarifications.

Obviously now it grew to a lot of speculations and many comments are far from real story. It is also really interesting to watch MySQL try to balance situation of maximizing revenues and minimizing missing off community at the same time. It is moving target and balance may shift in the future one direction or another depending on how things go.

Some of confusion I guess comes from my post where I speak about recent version and so recent binaries which were not available at that point. In many cases "recent" …

Some days ago I had the pleasure to interview Andrey Hristov, who is a developer at MySQL AB. He joined the team after working on a new feature for the MySQL Server as part of his master's thesis. You can read the full interview on the MySQL Developer Zone. Enjoy!

From: http://tinyurl.com/299h29

Oracle Updates Free SQL Developer Tools
Oracle Corp. has released the first major upgrade to SQL Developer, its free visual database development tool. The new version can browse non-Oracle databases, including Microsoft SQL Server and Access and MySQL AB?s open-source MySQL. The SQL Developer 1.1 tool simplifies the creation and debugging of code in standard SQL and in Oracle?s proprietary PL/SQL programming languages.

Roland Bouman has an excellent blog post on it:
http://rpbouman.blogspot.com/2007/01/oracle-sql-developer-11-supports-mysql.html