The MySQL replication system has always had the replication log (“binlog”) as a separate set of files on disk. Originally, this really didn’t matter as, well, MyISAM wasn’t transactional or crash safe so the binlog didn’t need to be either. If you crashed on a busy write workload, your replication was just going to be hosed anyway.

So then came a time where everybody used InnoDB. Transactional, crash-safe and all the goodies. Then, a bit later, came storing master rpl log position in InnoDB log and XA with the binlog. So a rather long time after MySQL first had replication, you could pull the power cord on the master with a decent amount of certainty that things would be okay when you turned it on again.

I am, of course, totally ignoring the slave state and if it’s safe to do that on slaves.

Using XA to make the binlog and InnoDB consistent does have a cost. That cost is fsync()s. You have to do a lot more of …

This tutorial explains how you can use NATURAL JOINs and what a natural join is actually. Included are syntax details and example statements.

Generally speaking, the keyword NATURAL can be treated as a join condition which is added implicitly. If used, it replaces the keywords ON and USING altogether. In MySQL writing natural joins means adding the keyword NATURAL to either an INNER JOIN or an OUTER JOIN. Let’s take a look at how a natural join implies a join condition.

Syntax

First of all, some natural join syntax examples. As mentioned earlier, a natural join adds a implicit condition to inner and outer join statements:

-- natural inner …

Giuseppe "The Data Charmer" Maxia recently posted his take on the MySQL forks. I had been pondering whether to do the same, and seeing that what I planned to write will nicely complement Giuseppe's article, I was inspired to follow him into the same topic. Note that last Spring I created a Map of MySQL forks in preparation for Monty's keynote at the MySQL user conference. So let's see how things have evolved. I'll look into MySQL ecosystem as a whole and the forks separately.

The post is long, but the key takeaway is that despite the challenges, the combined development seen in the MySQL ecosystem is probably stronger than ever, the current …

This tutorial shows you how to write straight joins in MySQL and when an it makes sense to do so. Included are a general description, syntax examples and a comparison of straight and inner joins.

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Straight Join

A STRAIGHT_JOIN identifies and combines matching rows which are stored in two related tables. This is what an inner join also does. The difference between an inner join and a straight join is that a straight join forces MySQL to read the left table first.

To see if the STRAIGHT_JOIN hint would make sense, you have to use EXPLAIN to analyze your queries. When you feel that another join order could improve the performance, use a straight join.

Left table?

The STRAIGHT_JOIN keyword or hint, forces MySQL …

There are three active projects to add support for group commit to MySQL/InnoDB. Monty Program and MySQL appear to have work in progress. The Facebook version is done but we will gladly undo it when official versions are ready.

PostgreSQL has group commit today. It is enabled by the commit_delay configuration parameter and the feature is described in the manual.

The commit_delay options provides a constraint on when group commit is done that has yet to be considered in …

The PERFORMANCE SCHEMA is dead

The initial implementation of the performance schema used to name tables in the performance schema database in UPPERCASE, as in 'EVENTS_WAITS_CURRENT'.

This naming scheme turned up to be difficult to work with (see Bug#57609), especially considering the established MySQL practice of converting table names to lowercase, using the lower_case_table_names server setting.

Long live the performance schema

Starting with MySQL 5.5.8, the performance schema tables have been renamed to lowercase.

This guarantees that a query such as 'select * from performance_schema.events_waits_current' will work consistently across any server deployment, regardless of the server platform or the server …

On Sunday I will be in Stuttgart with the double purpose of attending the annual European PostrgreSQL conference and the technical meeting of my company that will be held after the normal proceedings of PGDay-EU.
For the first time in several years I am attending a conference where I am not a speaker. In my previous job I did not have much opportunity to attend PostgreSQL meetings, and I welcome this opportunity. The schedule is quite interesting, and I have made my personal picks:

• Monday:
  
  • 09:45 - 10:45 …

New CEOs for Funambol and Openbravo. Funding for 10gen. And more.

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

# Funambol appointed Amit Chawla as its new CEO.

# Openbravo appointed Paolo Juvara as its new CEO and raised a new funding round.

# 10gen raised $6.5m in third-round funding led by Sequoia Capital.

# Microsoft has reportedly invested an undisclosed sum in TurboHercules.

# …

As part of the upcoming Oracle OpenWorld/Java One in São Paulo, Brazil next week (which will also include MySQL-related sessions), there will be a free MySQL Community event, which will take place on December 8th, from 13:00-18:00.

Here's the (translated and abbreviated) description from the events page:

Oracle invites you to attend the MySQL Community Forum! Don't miss an evening filled with technical sessions led by engineers and leaders of the MySQL open source community. You will have the opportunity to learn more about MySQL, Glassfish and what innovations to expect from MySQL 5.5.

This …

Oracle hasn't won many friends in open source communities since its acquisition of Sun Microsystems and Sun's array of open source assets, including MySQL, Java, and OpenOffice. Oracle seems bent on continuing this trend with the growing Hudson open source project.

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