The PHP BBQ Tour is almost over. There is one chance left for you to come to a BBQ and to meet Giuseppe Maxia, the Datacharmer and leader of the MySQL Community team. The closing meeting will be held today in Kiel at the restaurant (not in the garden, no real BBQ, just like in Munich!) of the Forstbaumschule at 16:00 CEST. Its a little change in the location but no change in time.

Change for Kiel (today): due to rainy weather conditions we meet at the Forstbaumschule restaurant not in the garden, no BBQ but a meeting, just like in Munich. Same time (16:00 CEST), almost the same place as before the change. Seats have been reserved, ask for Wendel/PHP.

We had to move the Kiel BBQ to the restaurant due to bad weather conditions. It is just like yesterday …

A long standing bugAmong the many outstanding bugs for MySQL, there is one that has sparked a fierce discussion, not only in the bug report itself, but also in blogs, forums, mailing lists.
Bug #19027: MySQL 5.0 starts even with Fatal InnoDB errors was neglected for long time, until finally it got fixed, and it is available in MySQL 5.1.36.
First off, what is it about?
In short, if an engine doesn't initialize correctly, the MySQL server starts anyway, without the offending engine. Depending on how you use the failing engine, this could be either a minor annoyance or a complete disaster.
Annoyance: ARCHIVE fails to initialize, and you create tables with the default engine (usually MyISAM), and after a while you realize that the disk is filling up faster than you expected. You will find out eventually.
Disaster: ARCHIVE fails to …

I spent some time earlier this week trying to debug a permissions problem in Drupal.

After a lot of head-scratching, it turned out that Drupal assumes that when you run INSERT queries sequentially on a table with an auto_increment integer column, the values that are assigned to this column will also be sequential, ie: 1, 2, 3, …

This might be a valid assumption when you are the only user doing inserts on a single MySQL server, but unfortunately that is not always the situation in which an application runs.

I run MySQL in a dual-master setup, which means that two sequential INSERT statements will never return sequential integers.  The value will always be determined by the  auto_increment_increment and auto_increment_offset settings in the configuration file.

In my case, one master will only assign even numbers, the other only uneven ones.

My …

They sometimes go bad in completely unpredictable ways. Here's a problem I have now seen twice in production situations. A host boots up nicely and mounts file systems from the SAN. At some point a SAN switch (e.g., through a Fibrechannel controller) fails in such a way that the SAN goes away but the file system still appears visible to applications.

This kind of problem is an example of a Byzantine fault where a system does not fail cleanly but instead starts to behave in a completely arbitrary manner. It seems that you can get into a state where the in-memory representation of the file system inodes is intact but the underlying storage is non-responsive. The non-responsive file system in turn can make operating system processes go a little crazy. They continue to operate but show bizarre failures or hang. The result is problems that may not be …

Sometime (rather I would say most of the time) you may need to restore a single/specific database from the nightly backup but unfortunately your nightly backup contains all the other databases and restoring all the databases is not the solution as we may end up losing some of the data which might be added to the databases after the nightly backup. Fortunately there is one option "--one-database" available in the 'mysql' command line utility which comes into our rescue.


In order to restore a single database from the nightly backup you can use the --one-database or -o option when restoring

shell>mysql --one-database required_db < /path/to/backup.sql

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After a long hiatus, I am happy to announce that mylvmbackup version 0.12 has now been released. This release includes a large number of improvements, minor code cleanups, as well as some new functionality. In particular, I would like to thank Matthew Boehm, Tim Stoop, Baron Schwartz, Ville Skyttä and Ronald Bradford for their contributions.

Some notable highlights from the ChangeLog:

• Removed the absolute path names to external tools (make sure $PATH is correct)
• Added --log-err to the startup options of the recovery instance to avoid cluttering the server's error log
• Added support for hooks written as Perl Modules. (Matthew Boehm)
• Added support for date/time-formatted path names for backupdir and mountdir (Matthew Boehm)
• Backupdir and …

I continue to try and find new ways to make it easier for people to get into the right place in the documentation for the information you are looking for.

This week, I’ve added some experimental custom indexes. These use information from the ID mapping process that we use in lots of parts of the documentation to do some interesting stuff.

The indexes are an extension of the other areas where we already provide summaries (like the list of options/variables, or functions). These provide quick access into the definition of the function, but not a link to where that function might have been mentioned elsewhere in the documentation. With the indexes, we’ve extended that so that you can now see all of the places within the reference manual where we mention a specific function. This goes beyond the index (which relies on us adding specific tags), and just lists everywhere that we mention a specific option.

Currently …

I will co-present in webinar on Performance Challenges and Solutions for IO Bound Workloads in MySQL. My part of the presentation will be speaking about why switching from CPU bound workload to IO bound is such an important event, how to prepare to it as well as how to keep your application performance good as the data growths.

The Brian's portion of webinar will focus on the Schooner offering as example of flash based appliance - one of solutions I mention in my presentation.

It should be interesting whenever you're interested in Schooner appliance offerings, flash or scaling MySQL in General.

You can follow this url to register.

Entry posted by peter | …

When writing queries, try making a habit out of using short table aliases, no matter how small the query is. Try using an alias that is as short as possible (one letter if possible, two or three when necessary) to avoid clutter in your queries.
Use these aliases in all places where you refer to a field, no matter if it would technically not be necessary. It will make your queries readable, and if you later need to join in other tables, you will not run the risk of ambiguous field names.

Let’s look at an example using the World database. The following two queries both select the 10 biggest cities by population in the continent of Africa, with a population between 1 and 1,5 million.

Good practice:

SELECT
  ci.name AS city_name,
  ci.district,
  co.name AS country_name,
  ci.population
FROM
  Country AS co
  INNER JOIN City AS ci ON …

As you may know, Iranian citizens do not have internet as the government has blocked almost all the websites (as well as phone calls and SMSs).
To help the Iranian people get information, please consider installing and using Tor to allow Iranians to anonymize themselves and see blocked websites.
سایت های اینترنت توسط دولت ایران مسدود شده است. به مردم ایران برای دیدن سایتهای مسدود شده با استفاده از یک برنامه خاص کمک کنیدTor







After installing you can help more effectively by providing your tor details directly to Iranian citizens by following this …