Great news! MySQL 8.0.3 is out and it is a release candidate. In the replication team we have been busy working on interesting new enhancements and also doing some clean up. Some of these new features are out in this release.…
Comparing Oracle MySQL Group Replication and Galera Cluster through a probability perpective seems quite interesting.
At commit time both use a group certification process that requires network round trips. The required time for these network roundtrips is what will mainly determined the cost of a transaction. Let us try to compute an estimate of the [...]
A MySQL replication topology can be very complex (never underestimate a DBA’s creativity). But it’s very frequent to use an asynchronous slave from your primary database to run reporting or logical backup… or any kind of read workload you need. It can also be used as delay slave for data restore purpose.
Once you decided to provide HA to your primary database by migrating to MySQL InnoDB Cluster, you can of course still need and use one or more asynchronous slaves.
You have then an architecture that looks like this :
So as you can notice, your asynchronous slave needs to pick one of the members of the cluster as master. However when this node that act as master crashes (or is stopped for maintenance) what’s happening ?
From September 25th to 27th 2017, the MySQL engineers and community team will be speaking at Percona Live Europe in Dublin.
MySQL is also part of the contributing sponsors.
For the conference, we tried to bring new faces to the Community. Usually, it’s always the same famous team leaders speaking at the conferences, this time, it’s not. A lot of key developers will present their own work. We have so much talented people in MySQL we want to present to our community.
Of course, once again we will focus our talks on MySQL 8.0. This is the list of sessions the MySQL Team will deliver:
Monday, Sep 25th
On Monday, I will deliver a tutorial with my friend …[Read more]
Today is my last day in Asia (China and Taiwan), and between the sessions I had the time to code a small proof-of-concept for people that are asking how they could read their writes on all nodes and ensure the read consistency with their last write ?
The usual (and easier) answer to this particular question is to read on the same host you just wrote. But currently MySQL provides you all the elements to force a consistent read across all the nodes of a group.[Read more]
Recently I wrote a blog post on how to use ProxySQL with 8.0.2 dmr
This blog post was related to the change we implemented in the Group Replication’s monitoring (performance_schema tables) and how sys schema should be changed to modify the view used by ProxySQL according.
However, I used my labs machines that I was using for different purposes too and some changes I made hid a problem that avoid ProxySQL to work with the new defaults in MySQL 8.0.2. Thank you Andy for discovering this.
In fact the new collation default (utf8mb4_0900_ai_ci) is not yet supported by ProxySQL …[Read more]
In this blog, we’ll look at group replication and how it deals with flow control (FC) and replication lag.
In the last few months, we had two main actors in the MySQL ecosystem: ProxySQL and Group-Replication (with the evolution to InnoDB Cluster).
While I have extensively covered the first, my last serious work on Group Replication dates back to some lab version years past.
Given that Oracle decided to declare it GA, and Percona’s decision to provide some level of Group Replication support, I decided it was time for me to take a look at it again.
We’ve seen a lot of coverage already too many Group Replication topics. There are articles about Group Replication and performance, Group Replication and basic functionalities (or lack of it like automatic node provisioning), Group Replication and ProxySQL, and so on.
But one question kept coming up over and over in my …[Read more]
Some time ago I wrote this article explaining how to find which node was the Primary Master in a MySQL Group Replication cluster running in Single-Primary Mode.
In the latest release of Group Replication, MySQL 8.0.2 dmr, Jaideep improved the visibility of Group Replication extending the performance_schema tables (see his article).
Thanks to these improvements, it’s now very easy to find which host is acting a Primary-Master. This is the query you can use:
mysql-sql> SELECT MEMBER_HOST as `PRIMARY` FROM performance_schema.replication_group_members WHERE MEMBER_ROLE='PRIMARY'; +---------+ | PRIMARY | +---------+ | mysql3 | +---------+ 1 row in set (0.00 sec) …[Read more]
In initial Group Replication release, 5.7.17, we included the Single-Primary Mode with automatic membership and fail-over features. The MySQL Server 8.0.2 release has brought further enhancement to Group Replication Single-Primary Mode that will allow users to influence primary member election using integer member weight value.…
Recently, my friend Marco Tusa(MySQL Daddy or the Grinch) wrote his first impression on MySQL Group Replication (part of InnoDB Cluster). And his conclusion was not that positive. But when I analyze his setup, I understand that his assumptions were not so right.
Let's try to explain what were the issues and why his test wasn't correct.
Before commenting Marco's tests, I would like to clarify the flow-control implementation in Group Replication:
We designed the flow-control feature in Group Replication as a safety measure for delaying writer nodes when they consistently exceed the write capacity of the Group, so that a large backlog would not make it hard to switch over from a member to another.
Flow-control is …[Read more]