Hi ZanyWeb. Here's a pop quiz for you, and the answer may surprise you.

The MySQL manual states the following about the REPLACE statement:

REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted.

Sounds pretty clear to me. If a row with the same primary key exists, it is deleted and then a new row is inserted.

So, given the above, if I execute the following statements in a client, what would you expect would happen behind the scenes in the storage engine?

CREATE TABLE t1 (
  id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
, padding VARCHAR(200) NOT NULL
);

INSERT INTO t1 VALUES (1, "I love testing.");
INSERT INTO t1 …

Michael "Monty" Widenius says the European Commission is right to be concerned about the Oracle-Sun merger and urges Oracle to sell MySQL to settle antitrust issues.

For easy MySQL failover, replication is a great solution. This post will cover the basics of performing a failover in case your master dies.

First, setup one-way replication (or two-way, but don't plan to use both servers for writes at the same time). Next, you'll want to direct all activity, or at least the writes, to the master. If the master dies, there are two major concerns:

1. Redirecting the clients to the slave. There are several ways to handle this, such as Heartbeat or MySQL's JDBC driver.
2. Checking if the slave is caught up. This is trickier. If the master's binary logs are still available, then you can do SHOW SLAVE STATUS on the slave and compare the READ_MASTER_LOG_POS to the master's binary log. For example, if SHOW SLAVE STATUS shows:
   Master_Log_File: localhost-bin.000051
…

The future of MySQL. The SCO Group terminates Darl McBride. And more.

The future of MySQL
Monty Widenius urged Oracle to give up on MySQL in order to land Sun while Richard Stallman, Knowledge Ecology International (KEI) and the Open Rights Group sent a letter to the EC urging it to block Oracle’s acquisition of MySQL. All of which prompted Florian Mueller, who it should be noted is working with Widenius as part of his campaign, to claim that there is growing public opposition to Oracle owning Sun’s MySQL.

Meanwhile The VAR Guy reported on rumours that …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …

Maatkit’s mk-loadavg tool is a helpful way to gather information about infrequent conditions on your database server (or any other server, really). We wrote it at Percona to help with those repeated cases of things like “every two weeks, my database stops processing queries for 30 seconds, but it’s not locked up and during this time there is nothing happening.” That’s pretty much impossible to catch in action, and these conditions can take months to resolve without the aid of good tools.

In this blog post I’ll illustrate a very simple usage of mk-loadavg to help in solving a much smaller problem: find out what is happening on the database server during periods of CPU spikes that happen every so often.

First, set everything up.

1. Start a screen session: …

MySQL's ex-CEO Marten Mickos and MySQL co-founder Michael "Monty" Widenius recently released open letters to the EU. Marten supports the Oracle acquisition of MySQL, as part of the Sun deal. Monty urges the EU to block MySQL from being controlled by Oracle.

read more

A controversial issue in the UK this week is the BBC’s decision to invite the British National Party - the far-right, whites-only political party - to appear on Question Time, the BBC’s flagship political debate programme.

Critics fear that the move will legitimise the BNP’s far-right views, while the BBC has defended the invitation on the grounds that its role as a politically neutral public service broadcaster would be undermined if it excluded the BNP - which won its first European Parliament seats this year with an estimated million votes.

To me it is clear that no matter how abhorrent the BNP’s policies on certain issues may be the BBC has a duty to invite it to participate as it is a legitimately recognised political party. We live in a society …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …