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Displaying posts with tag: Group Replication (reset)
Performance improvements in Percona XtraDB Cluster 5.7.17-29.20

In our latest release of Percona XtraDB Cluster, we’ve introduced major performance improvements to the MySQLwrite-set replication layer. In this post, we want to show what these improvements look like.

For the test, we used the sysbench OLTP_RW, UPDATE_KEY and UPDATE_NOKEY workloads with 100 tables, 4mln rows each, which gives about 100GB of datasize. In all the tests we use a three-node setup, connected via a 10GB network, with the sysbench load directed to the one primary node.

In the first chart, we show improvements comparing to the previous version (5.7.16):

The main improvements come from concurrent workloads, under multiple threads.

The …

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Group Replication GCS Troubleshooting

In the last post I shared the simple set of steps to configure a Group Replication setup using SQL commands, and a few in the configuration file too. Indeed, it can be simple.  But then there are times where there are more requirements and configurations need more attention. Maybe the OS environment we use for MySQL setups has never impacted us… Read More »

Percona Live Featured Session with Luís Soares: The New MySQL Replication Features in MySQL 8

Welcome to another post in the series of Percona Live featured session blogs! In these blogs, we’ll highlight some of the session speakers that will be at this year’s Percona Live conference. We’ll also discuss how these sessions can help you improve your database environment. Make sure to read to the end to get a special Percona Live 2017 registration bonus!

In this Percona Live featured session, we’ll meet Luís Soares, Principal Software Engineer at Oracle. His session is The New MySQL Replication Features in MySQL 8 (with fellow presenter Lars Thalmann, Development Director at Oracle). The most popular high availability …

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MySQL Group Replication: native support in ProxySQL

ProxySQL is the leader in proxy and load balancing solution for MySQL. It has great features like query caching, multiplexing, mirroring, read/write splitting, routing, etc… The latest enhancement in ProxySQL is the native support of MySQL Group Replication. No more need to use an external script within the scheduler like I explained in this previous post.

This implementation supports Groups in Single-Primary and in Multi-Primary mode. It is even possible to setup a Multi-Primary Group but dedicate writes on only one member.

René, the main developer of ProxySQL, went even further. For example in a 7 nodes clusters (Group …

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MySQL Group Replication: who is the primary master ??

As you know, MySQL Group Replication runs by default in single primary mode.

mysql2 mysql> show global variables like 'group_replication_single_primary_mode';
| Variable_name                         | Value |
| group_replication_single_primary_mode | ON    |

But how can we easily find which member of the group is the Primary-Master ?

Of course you could check which one is not in read_only:

mysql2 mysql> select @@read_only;
| @@read_only |
|           1 |

But then you need to perform this on all the nodes one by one until you find the right one.

The primary …

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Jeudis du Libre – Mons

Yesterday I was invited to speak at the “Jeudis du Libre” in Mons.

The location was very special as it was in one auditorium of Polytech, the oldest university in the city of Mons.

I presented in French two very hot topics in the MySQL ecosystem:

  • MySQL InnoDB Cluster
  • MySQL as Document Store with JSON datatype & X plugin

Those are very new technologies illustrating MySQL’s innovation. And of course there is much more to come with MySQL 8 !

Here are the slides if you are interested:

Jeudis du Libre – MySQL InnoDB Cluster from Frederic Descamps

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MySQL InnoDB Cluster: MySQL Shell starter guide

 Earlier this week,  MySQL Shell 1.08 has been released. This is the first Release Candidate of this major piece of MySQL InnoDB Cluster.

Some commands have been changed and some new ones were added.

For example the following useful commands were added:

  • dba.checkInstanceConfiguration()
  • cluster.checkInstanceState()
  • dba.rebootClusterFromCompleteOutage()

So let’s have a look on how to use the new MySQL Shell to create a MySQL InnoDB Cluster.

Action Plan

We have 3 blank Linux servers: mysql1, mysql2 and mysql3 all running rpm based Linux version 7 (Oracle Linux 7, CentOS 7, …).

We will install the required MySQL yum repositories and install the needed packages …

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MySQL Support Engineer's Chronicles, Issue #5

A lot of time passed since my previous post in this series. I was busy with work, participating in FOSDEM, blogging about profilers and sharing various lists of MySQL bugs. But I do not plan to stop writing about my usual weeks of doing support engineer's job. So, time for the next post in this series, based on my random notes taken during the week here and there.

This week started for me with checking recent MySQL bug reports (actually I do it every day). …

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Quest for Better Replication in MySQL: Galera vs. Group Replication

UPDATE: Some of the language in the original post was considered overly-critical of Oracle by some community members. This was not my intent, and I’ve modified the language to be less so. I’ve also changed term “synchronous” (which the use of is inaccurate and misleading) to “virtually synchronous.” This term is more accurate and already used by both technologies’ founders, and should be less misleading.

I also wanted to thank Jean-François Gagné for pointing out the incorrect sentence about multi-threaded slaves in Group Replication, which I also corrected accordingly.

In today’s blog post, I will briefly compare two major virtually synchronous replication technologies available today for MySQL.

More Than Asynchronous Replication

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MySQL Group Replication: about ack from majority

The documentation states that “For a transaction to commit, the majority of the group have to agree on the order of a given transaction in the global sequence of transactions.

This means that as soon as the majority of nodes member of the group ack the writeset reception, certification can start. So, as a picture is worth a 1000 words, this is what it looks like if we take the illustrations from my previous post:

a group of 3 members

zoom in transaction deliverthe writer also acksmajority is reached, the system agreed on the orderack of the remaining node will come too but the order has been already decided


certification can startthe process then continues as usual

So theoretically, having 2 nodes in one DC and 1 node in another DC shouldn’t be affected …

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