Replication is the process that transfers data from an active master to a slave server, which reproduces the data stream to achieve, as best as possible, a faithful copy of the data in the master.
To check replication health, you may start with sampling the service, i.e. committing some Sentinel value in the master and retrieving it from the slave.
When a new version of MySQL appears, the first source of information for the brave experimenter is a page in the manual named What is new in MySQL X.X, also known as MySQL in a nutshell. For MySQL 5.7, the in-a-nutshell page lists quite a lot of changes. In that page, the list of removed features is enough to send a chill down the spine of most any DBA.
Maintaining a project like MySQL::Sandbox is sometimes tiring, but it has its advantages. One of them is that everything related to the server setup comes to my attention rather earlier than if I were an average DBA or developer.
I try to keep MySQL Sandbox up to date with every release of MySQL and (to a lesser extent) MariaDB . For this reason, I am used to trying a new release with MySQL Sandbox, and … seeing it fail.
Both MySQL and MariaDB have been busy, each introducing new features, sometimes creating the same feature, often with different syntax.
Today Oracle released MySQL 5.7.6 milestone 16. With this, MySQL 5.7 has been in development for over 2 years.
Compared to MySQL 5.6, the changes are quite extensive. The main effort of the team has been focused on speed, with performance reportedly improved from 2 to 3 times compared to previous releases.
A full list of what is new would take too much space here, but I would like to mention some key points:
Using MySQL Sandbox I can install multiple instances of MySQL. It is not uncommon for me to run 5 or 6 instances at once, and in some occasions, I get to have even 10 of them. It is usually not a problem. But today I had an issue while testing MariaDB, for which I needed 5 instances, and I the installation failed after the 4th one. To make sure that the host could run that many servers, I tried installing 10 instances of MySQL 5.6 and 5.7. All at once, for a grand total of 20 instances:!-->!-->
MySQL, the original brand, the one developed by the MySQL team at Oracle, is steadily evolving. You can feel it if you try every new release that comes out of the milestone release cycle. Or even if you don’t try all of them, just testing a release once in a while gives you something to think about.!-->!-->
It has been a few busy months until now. I have moved from Italy to Thailand, and the move has been my first priority, keeping me from attending FOSDEM and interacting with social media. Now I start catching my breath, and looking around for new events to attend. But before I get into this, let’s make a few things clear:
In the last 10 years I have worked a lot with replication systems, and I have developed a keen interest in the topic of multiple masters in a single cluster. My interest has a two distinct origins: