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Displaying posts with tag: Percona XtraDB Cluster (reset)
Understanding Percona XtraDB Cluster threading model

In this blog, we’ll discuss how the Percona XtraDB Cluster threading model works.

Percona XtraDB Cluster (PXC) creates a different set of threads to service its operations. These threads are in addition to existing MySQL threads. Let’s understand what these threads are and how they’re used. There are three main groups of threads:

  1. Applier thread(s)
    1. Applier threads are meant to apply write-sets that the node receives from other nodes (through cluster). (write-message is directed through
      gcv_recv_thread
      
      .)
    2. The number of applier threads is controlled using the
      wsrep_slave_thread
      
       configuration. (The default value is 1, so at least one wsrep applier thread exists to …
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Percona XtraDB Cluster 5.6.28-25.14 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on January 29, 2016. Binaries are available from the downloads area or from our software repositories.

Percona XtraDB Cluster 5.6.28-25.14 is now the current release, based on the following:

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Percona XtraDB Cluster 5.6.27-25.13 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on January 11, 2016. Binaries are available from the downloads area or from our software repositories.

Percona XtraDB Cluster 5.6.27-25.13 is now the current release, based on the following:

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Better high availability: MySQL and Percona XtraDB Cluster with good application design

High Availability

Have you ever wondered if your application should be able to work in read-only mode? How important is that question?

MySQL seems to be the most popular database solution for web-based products. Most typical Internet application workloads consist of many reads, with usually few writes. There are exceptions of course – MMO games for instance – but often the number of reads is much bigger then writes. So when your database infrastructure looses its ability to accept writes, either because traditional MySQL replication topology lost its master or Galera cluster lost its quorum, why would you want to the application to declare total …

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A first look at RDS Aurora

Recently, I happened to have an onsite engagement and the goal of the engagement was to move a database service to RDS Aurora. Like probably most of you, I knew the service by name but I couldn’t say much about it, so, I Googled, I listened to talks and I read about it. Now that my onsite engagement is over, here’s my first impression of Aurora.

First, let’s describe the service itself. It is part of RDS and, at first glance, very similar to a regular RDS instance. In order to setup an Aurora instance, you go to the RDS console and you either launch a new instance choosing Aurora as type or you create a snapshot of a RDS 5.6 instance and migrate it to Aurora. While with a regular MySQL RDS instance you can create slaves, with Aurora you can add reader nodes to an existing cluster. An Aurora cluster minimally consists of a …

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Proxy Protocol and Percona XtraDB Cluster: A Quick Guide

On September 21st, we released Percona XtraDB Cluster 5.6.25. This is the first PXC release supporting proxy-protocol that has been included in Percona Server since 5.6.25-73.0.

With this blog post, I want to promote a new feature that you may have ignored.

Let’s start with a description of the use case:

Architecture Overview:

HAProxy is configured like this:

listen 3307-active-passive-writes 0.0.0.0:3307
    mode tcp
    balance …
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Percona XtraDB Cluster 5.6.26-25.12 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on October 15th 2015. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.26-74.0 including all the bug fixes in it, Galera Replicator 3.12, and on …

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Percona XtraDB Cluster 5.6.25-25.12 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on September 21st 2015. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.25-73.1 including all the bug fixes in it, Galera Replicator 3.12, and on …

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Clarification on “Call me Maybe: MariaDB Galera Cluster”

Recently Aphyr (Kyle Kingsbury) published https://aphyr.com/posts/327-call-me-maybe-mariadb-galera-cluster

The article is technically valid, I am not going to dispute a conclusion Aphyr made, but it is also quite technically involved, so users who just jump to conclusion may get the wrong impression and we’re left with more questions than ever.

So, let me state what is the real conclusion of this article:
“Galera cluster does not support SNAPSHOT ISOLATION LEVEL, in contract to what was stated in the documentation”.
Following that conclusion is using Galera cluster may result in “corrupted” data.

I do not quite like the usage of the word “corrupted” here. For me, the more correct word be to use is “inconsistent”.

So with this clarification, the …

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High-load clusters and desynchronized nodes on Percona XtraDB Cluster

There can be a lot of confusion and lack of planning in Percona XtraDB Clusters in regards to nodes becoming desynchronized for various reasons.  This can happen a few ways:

When I say “desynchronized” I mean a node that is permitted to build up a potentially large wsrep_local_recv_queue while some operation is happening.  For example a node taking a backup would set wsrep_desync=ON during the backup and potentially fall behind …

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