After a long wait, today I release MyQuery 3.3.0. For you who haven't seen MyQuery before, this is a Windows based interactive query tool for MySQL (sorry no Mac or Linux support this time) . The emphasis is much on script editing and running, and on the needs of the DBA, more than on the end user. Also, for the database designer, there is some cool stuff in here.

MyQuery supports running scripts up to a specific point in the script, or starting from a specific point and supports a kind of "edit and continue", so you can develop a script, run it til it breaks, correct the error, and then continue where you left off.

That is not all, after all these releases MyQuery has gained quite a few useful features. Script editing is done with the Scintilla color coded editor for examples, and there are tools for managing database objects such as tables, views and events.

Every release of MyQuery has a theme, and …

Few days ago I was working on a case where we needed to modify a lot of data before pushing it to sphinx – MySQL did not have a function to do the thing so I thought I’ll write MySQL Stored Function and we’ll be good to go. It worked! But not so well really – building the index, which was taking 10 minutes, was now taking 16 minutes. Then we added another MySQL function for different set of attributes and indexing speed went from 16 minutes to 26 minutes. I knew using UDF would be faster, but I had no idea how much. Have you ever wondered?

So what were the modifications we needed? It was couple very simple things – (1) two varchar columns needed leading nonalpha characters trimmed, so “123 ^&* …

I’ve been studying the source of iostat again and trying to understand whether all of its calculations I explained here are valid and correct. Two of the columns did not seem consistent to me. The await and svctm columns are supposed to measure the average time from beginning to end of requests including device queueing, and actual time to service the request on the device, respectively. But there’s really no instrumentation to support that distinction. The device statistics you can get from the kernel do not provide timing information about device queueing, only a) begin-to-end timing of completed requests and b) the time accumulated by requests that haven’t yet completed. I concluded that the await is correct, but the svctm cannot be.

I just looked at the …

After working with Linux operating system for quite sometime now, I have compiled a list of some of the most useful commands to help perform the day-to-day administrative tasks.

Overview

In some cases, MySQL creates internal temporary tables while processing queries.
On the base of the dimensions of the resultset MySQL will use the MEMORY engine AND/OR the MyISAM engine.
The difference is that MEMORY engine will handle the table in memory, while MyISAM will write it on disk.
A table created using the MEMORY engine can be automatically converted by the MySQL server if exceed the define threshold.

Then there are others circumstances which could create temporary tables using MEMORY but that can go to MyISAM (so disk) if too large:

• If there is an ORDER BY clause and a different GROUP BY clause, or if the ORDER BY or GROUP BY contains columns from tables other than the first table in the join queue;
• DISTINCT combined with ORDER BY may require a temporary table;
• In the case of the SQL_SMALL_RESULT option, MySQL uses an in-memory temporary table, unless …

For a long time, the MySQL Documentation Team has been providing CHM files for most MySQL documentation we publish. Like many other formats, CHM-format docs can be downloaded from http://dev.mysql.com/doc. CHM (Compiled HTML Help) has been the de facto standard help file format on Windows since 1997, but the technology behind it is outdated and has all kinds of quirks. The successor format introduced with Windows Vista is AP Help, but it hasn't taken off in practice so far. So, with CHM being outdated and AP Help spread anything but widely, lots of vendors have started providing documentation on Windows in PDF or HTML format.

Building CHM-format documentation is a challenge of its own. I'll not go into details here, so let me just state that it requires a dedicated Windows box (or VM), and while it can be automated using Power Shell commands, there's no way to find …

For a long time, the MySQL Documentation Team has been providing CHM files for most MySQL documentation we publish. Like many other formats, CHM-format docs can be downloaded from http://dev.mysql.com/doc. CHM (Compiled HTML Help) has been the de facto standard help file format on Windows since 1997, but the technology behind it is outdated and has all kinds of quirks. The successor format introduced with Windows Vista is AP Help, but it hasn't taken off in practice so far. So, with CHM being outdated and AP Help spread anything but widely, lots of vendors have started providing documentation on Windows in PDF or HTML format.

Building CHM-format documentation is a challenge of its own. I'll not go into details here, so let me just state that it requires a dedicated Windows box (or VM), and while it can be automated using Power Shell commands, there's no way to find …

For a long time, the MySQL Documentation Team has been providing CHM files for most MySQL documentation we publish. Like many other formats, CHM-format docs can be downloaded from http://dev.mysql.com/doc. CHM (Compiled HTML Help) has been the de facto standard help file format on Windows since 1997, but the technology behind it is outdated and has all kinds of quirks. The successor format introduced with Windows Vista is AP Help, but it hasn't taken off in practice so far. So, with CHM being outdated and AP Help spread anything but widely, lots of vendors have started providing documentation on Windows in PDF or HTML format.

Building CHM-format documentation is a challenge of its own. I'll not go into details here, so let me just state that it requires a dedicated Windows box (or VM), and while it can be automated using Power Shell commands, there's no way to find …

I will be at VLDB 2010 next week.  If anyone on this blog is attending and wants to catch up to discuss start ups and innovation in DB, NoSQL, Big Data etc drop me a line and I will try to meet up.

Good news. I was told by a colleague that the Dutch ISP XS4ALL is offering IPv6 connectivity to its retail customers. You can see here although the comments are in Dutch.  They also provide a list of ADSL routers which should work for their service. The Cisco name may not be surprising but this is [...]