For those with an interest in MySQL, this week at Oracle OpenWorld has gotten off to a great start.  Demonstrating how Oracle drives MySQL innovation Tomas' "State of the Dolphin" keynote on Monday gave a great overview of the new MySQL products that have recently been delivered:

• MySQL Installer for Windows
• New MySQL Security and Scalability features 
• New MySQL High Availability features 
• New early access features in the MySQL 5.6.3 Development Milestone Release ("DMR") 
• New early access features in the …

For those with an interest in MySQL, this week at Oracle OpenWorld has gotten off to a great start.  Demonstrating how Oracle drives MySQL innovation Tomas' "State of the Dolphin" keynote on Monday gave a great overview of the new MySQL products that have recently been delivered:

• MySQL Installer for Windows
• New MySQL Security and Scalability features 
• New MySQL High Availability features 
• New early access features in the MySQL 5.6.3 Development Milestone Release ("DMR") 
• New early access features in the …

tl;dr : New 'automatic' optimistic conflict detection functions available giving the best of both optimistic and pessimistic replication on the same data
MySQL replication supports a number of topologies, and one of the most interesting is an active-active, or master-master topology, where two or more Servers accept read and write traffic, with asynchronous replication between them.

This topology has a number of attractions, including :

• Potentially higher availability
• Potentially low impact on read/write latency
• Service availability insensitive to replication failures
• Conceptually simple

…

Proof-of-concept Tungsten support for MongoDB arrived last May, when I posted about our hackathon effort to replicate from MySQL to MongoDB.  That code then lay fallow for a few months while we worked on other things like parallel replication, but the period of idleness has ended.  Earlier this week I checked in fixes to Tungsten Replicator to add one-line installation support for MongoDB slaves.

MySQL to MongoDB replication will be officially supported in the Tungsten Replicator 2.0.5 build, which will be available in a few weeks.  However, you can try out MySQL to MongoDB …

Databases are the center of today’s web, enterprise and embedded applications, storing and protecting an organization’s most valuable assets and supporting business-critical applications. Just minutes of downtime can result in significant lost revenue and dissatisfied customers. Ensuring database highly availability is therefore a top priority for any organization.

The new MySQL Guide to High Availability solutions is designed to navigate users through the HA maze, discussing:

- The causes, effects and impacts of downtime;

- Methodologies to select the right HA solution;

- Different approaches to delivering highly available MySQL services;

- Operational best practices to meet Service Level Agreements (SLAs).

As discussed in the new Guide, selecting the high availability solution …

Databases are the center of today’s web, enterprise and embedded applications, storing and protecting an organization’s most valuable assets and supporting business-critical applications. Just minutes of downtime can result in significant lost revenue and dissatisfied customers. Ensuring database highly availability is therefore a top priority for any organization.

The new MySQL Guide to High Availability solutions is designed to navigate users through the HA maze, discussing:

- The causes, effects and impacts of downtime;

- Methodologies to select the right HA solution;

- Different approaches to delivering highly available MySQL services;

- Operational best practices to meet Service Level Agreements (SLAs).

As discussed in the new Guide, selecting the high availability solution …

When I talked about the usability improvements of Tungsten Replicator, I did not mention the procedure for upgrading. I was reminded about it by a question in the TR mailing list, and since the question was very relevant, I updated the Tungsten Cookbook with some quick upgrading instructions. A quick upgrading procedure is as important as the installer. Since we release software quite often, either because we have scheduled features to release or because of bug fixes, users want to apply a new release to an existing installation without much fuss. You can do the upgrade with a very quick and painless procedure. Let's suppose that you have installed one Tungsten Replicator cluster using this command:

#
# using tungsten-replicator 2.0.4
# …

I am looking for people who have a bunch of r/o slaves running, and who are using a load balancer to distribute queries across them.

The typical setup would be a PHP or Perl type of deployment with transient connections which end at the end of the page generation, and where a reconnect is being made at the next request serviced. The connect would go to the load balancer, which will forward it to any suitable database in the pool.

I am looking for people who are actually deploying this, and what strategies they have to cope with potential problems. I also would like to better understand what common problems are they needed to address.

Things I can imagine from the top of my head:

- Slave lag. Slave lag can happen on single boxes due to individual failures (battery on raid controller expires) or many boxes (ALTER TABLE logjams hierarchy). In the latter case boxes cannot be dropped from the …

MySQL built-in replication includes a concept called relay slave, which allows you to create hierarchical database clusters. You can do the same thing with Tungsten, and this can be done in more than one way. Let's start with two distinct clusters. We can follow the recipes in the Tungsten Cookbook to install a master / slave cluster in three separate hosts and a …