With a tongue in cheek, humorous tone, we turn the tables upside down on database best practices, illustrating all of the things you shouldn’t do, and what might happen if you ignore those important tasks.

 7 Ways To Crash A Database

I'm pleased to announce the release of Spider storage engine version 0.18.(RC)
http://spiderformysql.com/

The main changes in this version are following.
- Add table parameter "use_pushdown_udf".
- Add server parameter "spider_use_pushdown_udf".
  "use_pushdown_udf" and "spider_use_pushdown_udf" are used for sending UDF string to remote server if engine_condition_pushdown is used.

From this version, you can use '\r' and '\n' like a space between table parameter name and table parameter value.
Thanks to Akihiro for report.

Please see "99_change_logs.txt" in the download documents for checking other changes.

Enjoy!

In my last post I included some sample data which was useful for playing around with queries (once I published it, I realized it made my post look like some form of keyword stuffing, fortunately I don’t use adsense on my site so I hope I’m free of any suspicion :D). That sample data was … Continue reading Generating data with dbmonster →

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We’re proud to announce the first service release of our current GA product MySQL Workbench 5.1. This maintenance release encompasses a number of stability, performance and quality improvements.
We were able to fix 56 bugs – as always, details on latest changes can be found on our Releases Page.

Please head over to our download page and fetch this new update:

http://dev.mysql.com/downloads/workbench/5.1.html

In addition to the improvements on the application, we also updated our packaging procedure to provide a more up to date selection of packages for recent distributions. Along with the Windows and OSX (intel) binaries we now provide binaries for the following Linux distributions:

Ubuntu 8.04  …

In July several Monty Program employees attended the Community Leadership Summit and O’Reilly’s Open Source Convention (OSCON), myself included. While there we spoke to developers, partners, users, and interested bystanders of a number of SQL servers: MariaDB, MySQL, Postgres, and others.

The week started with the Community Leadership Summit. First, a big thank you to Jono Bacon for organizing a fantastic unconference, and allowing us to participate! Monty Program considers it our privilege to have helped to sponsor the event, and we look forward to attending and …

This note describes how network IO is done using MySQL 5.0.84 on a modern Linux distribution. This description might be incorrect for other platforms because the code has many ifdefs. The functions my_real_read and net_real_write in sql/net_serv.cc read/write data to/from a socket. I describe the implementation of my_real_read but net_real_write is similar.

I am interested in this code because it uses the pthread mutex LOCK_alarm and there is a lot of contention for that mutex. I think this code can be made much more efficient. The basic problem is that when MySQL is compiled without defining NO_ALARM, the server uses an alarm thread rather than SO_SNDTIMEO and SO_RCVTIMEO to implement read/write with a timeout. For server-side code, NO_ALARM is only defined for Windows builds.

I think the server should be compiled so that SO_SNDTIMEO and SO_RCVTIME are used. Hopefully someone can comment on the history of this.

Pseducode …

Here's a quick list of common mistakes that I've seen regarding indexing in MySQL.

1. Not using an index. Enable your slow query log (and consider setting long_query_time and log_queries_not_using_indexes too) and watch for queries that aren't using an index.

2. Using CREATE INDEX. While CREATE INDEX is not inherently bad, it only allows you to do one thing: add a single index to a table. It is mapped to an ALTER TABLE, so you might as well just use ALTER TABLE and then you have the benefit of being able to do multiple things in the same statement (e.g., add an index and remove an index or add 2 indexes).

3. Misusing a composite index. Take this example:
CREATE TABLE customer (
custid INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
fname VARCHAR(30),
lname VARCHAR(30),
INDEX (lname, fname)
);

The composite index on (lname, fname) can be used for searches …

This is the 158th edition of Log Buffer, the weekly review of database blogs.

SQL Server

Simon Sabin has a TSQL Challenge – counting non zero columns. He says, “I’m working on a project where I need to cycle a flag amongst a set of columns. To achieve this I am storing a position value in each column which allows me to cycle them . . .  So the challenge is to find out the how many non zero columns there are, the twist is to use as little code as possible.”

On a cue from Simon, Aaron Bertrand shares …

Peter Fenton’s open source investment tips. Boxee raises $6m. And more.

Follow 451 CAOS Links live @caostheory on Twitter and Identi.ca
“Tracking the open source news wires, so you don’t have to.”

*451 CAOS Links will return on August 25*

Digesting the VMware-SpringSource deal
In the wake of VMware’s acquisition of SpringSource the WSJ examined Peter Fenton’s open source investment portfolio and what he looks for in an open source vendor. Meanwhile Matt Asay noted that VMware’s purchase of SpringSource is the first big acquisition of a company based on an Apache license, while Charles Babcock reported …