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Displaying posts with tag: Percona XtraDB Cluster (reset)
Galera Cache (gcache) is finally recoverable on restart

This post describes how to recover Galera Cache (or gcache) on restart.

Recently Codership introduced (with Galera 3.19) a very important and long awaited feature. Now users can recover Galera cache on restart.

Need

If you gracefully shutdown cluster nodes one after another, with some lag time between nodes, then the last node to shutdown holds the latest data. Next time you restart the cluster, the last node shutdown will be the first one to boot. Any followup nodes that join the cluster after the first node will demand an SST.

Why SST, when these nodes already have data and only few write-sets are missing? The DONOR node caches missing write-sets in Galera cache, but on restart this cache is wiped clean and restarted fresh. So the DONOR node …

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Webinar Q/A: MySQL High Availability with Percona XtraDB Cluster 5.7

In this blog I will provide answers to the questions and queries that some of you have raised during the webinar on Nov 17th.

I would like to say thank you to all of the audience who attended the talk on November 17, 2016. You can also check the recording and slides here.

Q. How is storage distribution done across the node?

A. Each node has independent storage and other resources. There is no sharing of resource. Only the write-sets are replicated.

Q. If write-set propagation fails in some manner is there any retry mechanism?

A. write-set are written to …

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Percona Server 5.5.53-38.4 is now available

Percona announces the release of Percona Server 5.5.53-38.4 on November 18, 2016. Based on MySQL 5.5.53, including all the bug fixes in it, Percona Server 5.5.53-38.4 is now the current stable release in the 5.5 series.

Percona Server is open-source and free. You can find release details in the 5.5.53-38.4 milestone on Launchpad. Downloads are available here and from the Percona Software Repositories.

Removed Features:

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All You Need to Know About GCache (Galera-Cache)

This blog discusses some important aspects of GCache.

Why do we need GCache?

Percona XtraDB Cluster is a multi-master topology, where a transaction executed on one node is replicated on another node(s) of the cluster. This transaction is then copied over from the group channel to Galera-Cache followed by apply action.

The cache can be discarded immediately once the transaction is applied, but retaining it can help promote a node as a DONOR node serving write-sets for a newly booted node.

So in short, GCache acts as a temporary storage for replicated transactions.

How is GCache managed?

Naturally, the first choice to cache these write-sets is to use memory allocated pool, which is governed by gcache.mem_store. However, this is deprecated and buggy and shouldn’t be used.

Next …

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Webinar Thursday, November 17: MySQL High Availability with Percona XtraDB Cluster 5.7

Join Percona’s Percona XtraDB Cluster Lead Software Engineer Krunal Bauskar for a webinar on Thursday, November 17, 2016, at 7:30 am PST on MySQL High Availability with Percona XtraDB Cluster 5.7.

Percona XtraDB Cluster 5.7 is our brand new MySQL 5.7 compatible Galera-based high availability (HA) solution. Whether you’re new to MySQL clustering technology, or experienced with Galera-based replication, this tutorial provides great insights into working with the software, …

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Percona responds to CVE-2016-6663 and CVE-2016-6664

Percona has addressed CVE-2016-6663 and CVE-2016-6664 in releases of Percona Server for MySQL and Percona XtraDB Cluster.

Percona is happy to announce that the following vulnerabilities are fixed in current releases of Percona Server for MySQL and Percona XtraDB Cluster:

  • CVE-2016-6663: allows a local system user with access to the affected database in the context of a low-privileged account (CREATE/INSERT/SELECT grants) to escalate their privileges and execute arbitrary code as the database system user (typically “mysql”).
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Percona Monitoring and Management (PMM) Information Script

This blog post discusses an information script for the Percona Monitoring and Management (PMM) tool.

In recent news, we announced the fresh-of-the-press Percona Monitoring and Management (or PMM for short) platform. Given the interaction of the different components that together make up PMM, I developed a script that helps provide you information about the status of your PMM installation.

You can use this script yourself, or one of our support might point you to this page to obtain the information they need to troubleshoot an issue you are experiencing.

You will likely want to execute this script once on the PMM …

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Replication Triggers a Performance Schema Issue on Percona XtraDB Cluster

In this blog post, we’ll look at how replication triggers a Performance Schema issue on Percona XtraDB Cluster.

During an upgrade to Percona XtraDB Cluster 5.6, I faced an issue that I wanted to share. In this environment, we set up three Percona XtraDB Cluster nodes (mostly configured as default), copied from a production server. We configured one of the members of the cluster as the slave of the production server.

During the testing process, we found that a full table scan query was taking four times less in the nodes where replication was not configured. After reviewing mostly everything related to the query, we decided to use perf.

We executed:

perf record -a -g -F99 -p $(pidof mysqld) -- sleep 60

And the query in another terminal a couple of times. …

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Consul Architecture

In this blog post, I’ll provide my thoughts about Consul for ProxySQL service discovery and automation.

I approached Consul recently while looking for a service discovery and configuration automation solution for ProxySQL. My colleague Nik Vyzas wrote a great post on this topic, and I suggest you read it. I wrote this article to share my first impressions of Consul (for whomever it might interest).

Consul is a complete service discovery solution. In this respect it differs from its alternative etcd, which only provides a foundation to build such solutions.

Consul consists of a single, small binary (the Linux binary is 24MB). You just download it, edit the configuration file and start the program. It doesn’t …

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Percona XtraDB Cluster 5.6.32-25.17 is now available

Percona announces the new release of Percona XtraDB Cluster 5.6.32-25.17 on October 4, 2016. Binaries are available from the downloads area or our software repositories.

Percona XtraDB Cluster 5.6.32-25.17 is now the current release, based on the following:

  • Percona Server 5.6.32-78.1
  • Galera Replication library 3.17
  • Codership wsrep API version 25

Bugs Fixed:

  • Fixed DONOR
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