As of MySQL 5.5.41, released on November 28 (last week), Oracle has fixed MySQL Bug 67433, which I filed on October 31, 2012 and wrote about 4 months ago in Stupid and dangerous: SET GLOBAL sql_log_bin. You can see the fix in Launchpad revision 4718.

The MySQL 5.5.41 release notes mention:

Replication: The global scope for the sql_log_bin system variable has been deprecated, and this variable can now be set with session scope only. The statement SET GLOBAL SQL_LOG_BIN now produces an error. It remains possible for now to read the global value of sql_log_bin, but you …

In my last post I covered how to use the query rewrite framework to write your own pre-parse plugin. The interface is simplistic: a string goes in, a string comes out, and the rest is up to your plugin’s internal workings. It doesn’t interact that much with the server. Today I am going to show you the other type of plugins that rewrite queries, post-parse query rewrite plugins. This type is, out of necessity, more tightly coupled with the server; it operates on the internal data structures that make up the query’s parse tree.

Creating the Plugin

Declaring the plugin is similar to declaring a pre-parse plugin: you declare the plugin in the usual way but with the addition of a specific plugin descriptor for the post-parse query rewrite plugin type. This is a struct, as usual:

struct …

One new feature in Percona XtraDB Cluster (PXC) in recent releases was the inclusion of the ability for an existing cluster to auto-bootstrap after an all-node-down event.  Suppose you lose power on all nodes simultaneously or something else similar happens to your cluster. Traditionally, this meant manually re-bootstrapping the cluster, but not any more.

How it works

Given the above all-down situation, if all nodes are able to restart and see each other such that they all agree what the state was and that all nodes have returned, then the nodes will make a decision that it is safe for them to recover PRIMARY state as a whole.

This requires:

• All nodes went down hard — that is; a kill -9, kernel panic, server power failure, or similar event
• All nodes from the last PRIMARY component are restarted …

This post is a follow-up to my November 19 webinar, “Tips from the Trenches: A Guide to Preventing Downtime for the Over-Extended DBA,” during which I described some of the most common reasons DBAs experience avoidable downtime. The session was aimed at the “over-stretched DBA,” identified as the MySQL DBA short of time or an engineer of another discipline without the depth of the MySQL system. The over-stretched DBA may be prone to making fundamental mistakes that cause downtime through poor response time, operations that cause blocking on important data or administrative mishaps through the lack of best practice monitoring and alerting. (You can download my slides and view the recorded webinar here.)

Monitor the things
One of the aides to keeping the system up and …

Amazon recently announced RDS Aurora a new addition to their database as a service offerings. Here’s Mark Callaghan’s take on what’s happening under the hood and thoughts from Fusheng Han. Amazon is uniquely positioned with RDS to take on offerings like Clustrix. So it’s definitely worth reading Dave Anselmi’s take on Aurora. Join 28,000 others […]

The Perfect Server - CentOS 7 x86_64 (nginx, Dovecot, ISPConfig 3)

This tutorial shows how to prepare a CentOS 7 x86_64 server for the installation of ISPConfig 3, and how to install ISPConfig 3 on it. ISPConfig 3 is a webhosting control panel that allows you to configure the following services through a web browser: nginx web server, Postfix mail server, MySQL, BIND nameserver, PureFTPd, SpamAssassin, ClamAV, Mailman, and many more. Since version 3.0.4, ISPConfig comes with full support for the nginx web server in addition to Apache; this tutorial covers the setup of a server that uses nginx, not Apache. The ISPConfig 3 apache perfect server tutorial is available here.

By default in MySQL 5.6, each time MySQL is started (regular start or crash recovery), it iterates through all the binlog files when GTIDs are not enabled. This can take a very long time if you have a large number of binary log files. MySQL and Percona Server 5.6.21+ have a fix with the simplified-binlog-gtid-recovery option. Let’s explore this issue.

Understanding the issue

It was first reported by Yoshinori @ Facebook (bug #69097).

Let’s start by looking at a MySQL 5.6 instance where binary logging is enabled but GTIDs are disabled.

If we restart MySQL with strace, we’ll see:

# strace -e open service mysql start
[...]
open("/var/lib/mysql5621/mysql-bin.000004", O_RDONLY) = 13 …

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The stripped down stored procedure shown below will accept any Data Manipulation Language statement as its parameter and automatically log the statement and create table backup copies before the statement is executed. The logging functionality is similar to MySQL's binary log but exclusive to DML statements and is useful for table data recovery operations, such as undoing the last table data change or to revert databases back to a certain point in time. All this is done exclusively using stored routines (procedures and functions).

Its assumed that the databases and tables that will be used are already formed to specific business requirements since DDL statements will not be logged by the stored procedure. Though logging of table data changes can also be achieved using triggers, it is not practical to alter each and …

December 1, 2014 By Severalnines

MariaDB 10 supports multi-source replication, and each MariaDB Galera node can have up to 64 masters connected to it. So it is possible to use a MariaDB Cluster as an aggregator for many single-instance MariaDB master servers.

In this blog post, we are going to show you how to setup multi-source replication with MariaDB Galera Cluster, where one of the Galera nodes is acting as slave to 3 MariaDB masters (see diagram below). If you would like to set this up with Percona XtraDB Cluster or Galera Cluster (Codership), please read this post instead.

MariaDB GTID vs MySQL GTID

MariaDB has a different implementation of Global Transaction ID (GTID), and is enabled by default starting from MariaDB 10.0.2. Multi-source replication in MariaDB works …

I spent the last 4 years at SkySQL/MariaDB working on versions of MySQL that could be “suitable for the cloud”. I strongly believed that the world needed a version of MySQL that could work in the cloud even better than its comparable version on bare metal. Users and administrators wanted to benefit from the use of cloud infrastructures and at the same time they wanted to achieve the same performance and overall stability of their installations on bare metal. Unfortunately, ACID-compliant databases in the cloud suffer from the issues that any centrally controlled and strictly persistent system can get when hosted on highly distributed and natively stateless infrastructures.
In this post I am not going to talk about the improvements needed for MySQL in the cloud - I will tackle this topic in a future post. Today I'd like to focus on the business side of RDS and Aurora. 
In the last 4 years I had endless discussions over …