I'm pleased to announce the release of Spider storage engine version 0.16.(beta)
http://spiderformysql.com/

The main changes in this version are following.
- Add server parameter "spider_same_server_link" and "spider_table_init_error_interval".
  "spider_same_server_link" is used for creating table link to same MySQL server's table.
  "spider_table_init_error_interval" is used for protection from connection consumption of eternal loop of table link. Please increase this parameter using "set global" command if eternal loop of table link causes connection consumption.

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

Enjoy!

I’ve been editing a task description in our worklog:
WL#411 Computed virtual columns as MS SQL server has.

The quirky thing about the description, nowadays, is that the columns aren’t necessarily computed, aren’t necessarily virtual, and — if anybody follows the general policy that we should be like the standard — won’t much resemble SQL Server. So it’s not a very good name, eh?

The topical thing about the description is that it differs from a bugs.mysql.com feature request
Bug#46491 Patch: Virtual columns (WL#411). This is another name that could be questioned, since in reality the patch doesn’t look like WL#411. (And before I edited the specification, the resemblance was no better.) Yet it’s perfectly acceptable, as evidenced by the fact that a non-MySQL …

I was fortunate enough to speak with Marcin Zukowski earlier about VectorWise.  If you missed it, VectorWise came out of stealth mode a day or two ago.  The have announced a joint partnership with Ingres and essentially are claiming impressive analytic RDBMS performance gains on conventional hardware.

To start with, a key message that I think needs to be communicated here is that this is not a product announcement.  Ingres and VectorWise have announced a partnership in which they of course plan to build products together, today those products are still in the works.

VectorWise is a spin out of CWI based on research that was undertaken by Marcin and others, research …

We have been trying to understand the cause of a bottleneck that causes intermittent query pileups. By pileup I mean that the number of concurrent queries jumps from 10 to 1000 in a few seconds and stays high for 10 or more seconds. Query response time increases significantly during a pileup. Users tend to dislike that.

Debugging, step 1

I think that bug 46459 is the cause. The search for the bug was interesting. We started with monitoring data from a subset of iostat, vmstat, SHOW STATUS and SHOW INNODB STATUS counters using a sample interval of more than 30 seconds. The data from this wasn't sufficient to understand the problem so we deployed mstat.py to sample counters more frequently on selected machines. While it would be great for my debugging efforts to always sample all counters every second, such a change would overwhelm the monitoring infrastructure and …

One of the things about working with MySQL Community is trying to reach you all. If you are reading this then we have reached you.  Talking about community is frankly about where our community exists, where you chat and feel comfortable. To that end we've created a poll about where you might be intrested in hearing *from* us. Please, do let us know which social network you are interested in here from us!

There is no ulterior motive, the poll is anonymous, but it gives us some crucial information on where you want to interact with us, or where we might begin to ask the questions.

Check out the poll.

Welcome to the 156th edition of Log Buffer, the weekly review of database blogs.

Oracle

Jonathan Lewis gets things rolling with his post, Empiricism. Jonathan asks his readers if an empirical approach to tuning would be appropriate for a particular wait scenario.

Doug Burns was also looking into wait times, beginning, “Sometimes you think a subject is understood so well, including by yourself, that you tend to overlook it until asked to explain it. That which seems intuitive to us …

MySQL GIS functions don't seem to include a Midpoint function; it's trivial to write one, but I thought posting this might save someone a few minutes. Enjoy!

DROP FUNCTION IF EXISTS midpoint;
DELIMITER //
CREATE FUNCTION midpoint(line GEOMETRY)
RETURNS POINT DETERMINISTIC
BEGIN

IF NumPoints(line) != 2 THEN
RETURN NULL;
END IF;

RETURN GeomFromText(CONCAT('POINT(',(X(StartPoint(line)) +X(EndPoint(line))) / 2,' ',(Y(StartPoint(line))+Y(EndPoint(line))) / 2,')'));
END //
DELIMITER ;

The feature I announced some time ago http://www.mysqlperformanceblog.com/2009/06/08/impossible-possible-moving-innodb-tables-between-servers/ is now available in our latest releases of XtraBackup 0.8.1 and XtraDB-6.

Now I am going to show how to use it (the video will be also available on percona.tv).
Let's take tpcc schema and running standard MySQL ® 5.0.83, and assume we want to copy order_line table to different server. Note I am going to do it online, no needs to lock or shutdown server.

To export table you need XtraBackup, and you can …

I'm pleased to announce the release of the Memcached Functions for MySQL, version 1.0.

This release contains several changes, per the ChangeLog:

1.0 Thursday, July 30, 2009 12:00:00 EST 2009
* Fixed issue of setting NULLs with user-defined variables (Thanks to
Jean-Jacques Moortgat at aol dot com !)
* Fixed issue of obtaining a NULL value FROM memcached
* All set functions now return 0 (failure) or 1 (success)
* Other cleanups
* More tests

Importantly, there was an issue that I blogged about several days ago where in the UDF API, if you pass a user-defined variable that is set to NULL to memc_set(), the length of the argument is 8192 even though the value of the argument itself is NULL, which caused much unhappiness in MySQL (crash). That is fixed by setting the length to 0 if the argument itself is NULL. Also fixed is obtaining the NULL value from memcached using …

When open source goes bad. Is open source a success or failure? 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.”

When open source goes bad
The H reported on the apparent turmoil at the CentOS project, while Jay Lyman offered the CAOS perspective. Meanwhile Slashdot reported that Alan Cox has quit as Linux TTY subsystem maintainer.

Success or failure?
Danny Windham, Digium CEO, …