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Displaying posts with tag: Group Replication (reset)
MySQL Group Replication: who is the primary master – updated!

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) …
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Group Replication: Prioritise member for the Primary Member Election

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.…

MySQL Group Replication is sweet… but can be sour if you misunderstand it ;-)

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 …

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Group Replication – Extending Group Replication performance_schema tables

In MySQL 8.0.2, users will see the additional columns in the existing Group Replication Performance Schema tables which will provide extended information about Group Replication. Now user can view role and MySQL version of each member of the group, which earlier required a complex set of query.…

Protecting your data! Fail-safe enhancements to Group Replication.

Group Replication has been around for some time now and the feedback from community is overwhelming. One of the suggestions (BUG#84795) received is related to deploying a mechanism to prevent a server from being updated after stopping group replication.…

MySQL 8.0.2 is out, some change is required to still use ProxySQL with GR

As you may know by now, MySQL 8.0.2 DMR is out ! \o/

Many features have been added (see Geir Høydalsvik‘s announcement) and of course the replication also brought new features and improvements (see this post from Luís Soares).

But some improvements in the monitoring broke the added sys view used by ProxySQL to monitor the state of a member of the group:

mysql> select * from sys.gr_member_routing_candidate_status;
+------------------+-----------+---------------------+----------------------+
| viable_candidate | read_only | transactions_behind | transactions_to_cert | …
[Read more]
Replication Features in MySQL 8.0.2

MySQL 8 is shaping up quite nicely. And we are having a blast in the MySQL replication team while this is happening. We are continuously improving all-things-replication by introducing new and interesting features. In addition, we have been listening to our community and addressing their feedback.…

MySQL Group Replication: understanding Flow Control

When using MySQL Group Replication, it’s possible that some members are lagging behind the group. Due to load, hardware limitation, etc… This lag can become problematic to keep good certification behavior regarding performance and keep the possible certification failure as low as possible. Bigger is the applying queue bigger is the risk to have conflicts with those not yet applied transactions (this is problematic on Multi-Primary Groups).

Galera users are already familiar with such concept. MySQL Group Replication’s implementation is different 2 main aspects:

  • the Group is never totally stalled
  • the node having issues doesn’t send flow control messages to the rest of the group asking for slowing down

In fact, every member of the Group send some statistics about its queues (applier queue and certification queue) to the other members. Then every node decide to slow down or not if they …

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The MySQL High Availability Landscape in 2017 (The Elders)

In this blog, we’ll look at different MySQL high availability options.

The dynamic MySQL ecosystem is rapidly evolving many technologies built around MySQL. This is especially true for the technologies involved with the high availability (HA) aspects of MySQL. When I joined Percona back in 2009, some of these HA technologies were very popular – but have since been almost forgotten. During the same interval, new technologies have emerged. In order to give some perspective to the reader, and hopefully help to make better choices, I’ll review the MySQL HA landscape as it is in 2017. This review will be in three parts. The first part (this post) will cover the technologies that have been around for a long time: the elders. The second part will focus on the technologies that are very popular today: the adults. Finally, the last part will try to extrapolate which technologies could become popular in the upcoming years: the …

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Upcoming HA Webinar Wed 6/21: Percona XtraDB Cluster, Galera Cluster, MySQL Group Replication

Join Percona’s MySQL Practice Manager Kenny Gryp and QA Engineer, Ramesh Sivaraman as they present a high availability webinar around Percona XtraDB Cluster, Galera Cluster, MySQL Group Replication on Wednesday, June 21, 2017 at 10:00 am PDT / 1:00 pm EDT (UTC-7).

Register Now

What are the implementation differences between Percona XtraDB Cluster 5.7, Galera Cluster 5.7 and MySQL Group Replication?

  • How do they work?
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