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Understanding how an IST donor is selected

In a clustering environment, we often see a node that needs to be taken down for maintenance. For a node to rejoin, it should re-sync with the cluster state. In PXC (Percona XtraDB Cluster), there are 2 ways for the rejoining node to re-sync: State Snapshot Transfer (SST) and Incremental State Transfer (IST). SST involves a full data transfer (which could be time consuming). IST is an incremental data transfer whereby only missing write-sets are donated by a DONOR to the rejoining node (aka as JOINER).

In this article I will try to show how a DONOR for the IST process is selected.

Selecting an IST DONOR

First, a word about gcache. Each node retains some write-sets in its cache known as gcache. Once this gcache is full it is purged to make room for new write-sets. Based on gcache configuration, each node may retain a different span of write-sets. The wider the span, the greater the probability of the node acting as …

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SQLyog MySQL GUI 12.5 Released

This new release of SQLyog primarily addresses a long-time concern by corporate users preferring to do a ‘silent installation’ over the corporate network. Even though ‘silent installation’ already was possible, every instance still had to be registered interactively from the workstation by every user. Now registration details can be applied on the command-line as well when doing a ‘silent install’. In addition to command-line this has been tested with a number of 3rd party softwares used by corporations for managing a centralized software repository and for centralized software management.

Changes as compared to MySQL GUI 12.4.3 include:

Features:

* Added command-line syntax for applying registration details when doing a ‘silent install’. You may refer …

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ZFS from a MySQL perspective

Since the purpose of a database system is to store data, there is close relationship with the filesystem. As MySQL consultants, we always look at the filesystems for performance tuning opportunities. The most common choices in term of filesystems are XFS and EXT4, on Linux it is exceptional to encounter another filesystem. Both XFS and EXT4 have pros and cons but their behaviors are well known and they perform well. They perform well but they are not without shortcomings.

Over the years, we have developed a bunch of tools and techniques to overcome these shortcomings. For example, since they don’t allow a consistent view of the filesystem, we wrote tools like Xtrabackup to backup a live MySQL database. Another example is the …

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MariaDB 10.1.29, MariaDB Galera Cluster 10.0.33 and MariaDB Connector/J Releases now available

The MariaDB project is pleased to announce the availability of MariaDB 10.1.29, MariaDB Galera Cluster 10.0.33 and MariaDB Connector/J 2.2.0. See the release notes and changelogs for details. Download MariaDB 10.1.29 Release Notes Changelog What is MariaDB 10.1? MariaDB APT and YUM Repository Configuration Generator Download MariaDB Galera Cluster 10.0.33 Release Notes Changelog What is […]

The post MariaDB 10.1.29, MariaDB Galera Cluster 10.0.33 and MariaDB Connector/J Releases now available appeared first on MariaDB.org.

Webinars on Wednesday November 15, 2017: Proxy Wars and Percona Software Update for Q4

Do you need to get to grips with MySQL proxies? Or maybe you could do with discovering the latest developments and plans for Percona’s software?

Well, wait no more because …

on Wednesday November 15, 2017, we bring you a webinar double bill.

Join Percona’s Chief Evangelist, Colin Charles as he presents “The Proxy Wars – MySQL Router, ProxySQL, MariaDB MaxScale” at 7:00 am PST / 10:00 am EST (UTC-8).

Reflecting on his past experience with MySQL proxies, Colin will provide a short review of three open source solutions. He’ll run through a comparison of MySQL Router, MariaDB MaxScale and ProxySQL and talk about the reasons for using the right tool for an application.

…

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MySQL Adds Fedora 27 Support

Fedora 27 is here, and we congratulate the Fedora community on another rev of one of the most popular Linux distros out there. Continuing our tradition of supporting new Linux distro versions from day one, we have added the following MySQL products to our official MySQL yum repos: MySQL Server 5.7.20 and 8.0.3 (which is […]

XtraBackup vs. OOM killer(usage of mprof)

This small article is about nicely depicting memory usage prior to OOM killers show.

I have started MySQL with:

/home/shahriyar.rzaev/XB_TEST/server_dir/PS131117-percona-server-5.7.19-17-linux-x86_64/bin/mysqld --no-defaults \
--innodb_buffer_pool_size=1G --innodb_log_file_size=1G --innodb_page_size=64K --early-plugin-load=keyring_file.so \ --keyring_file_data=/home/shahriyar.rzaev/XB_TEST/server_dir/PS131117-percona-server-5.7.19-17-linux-x86_64/mysql-keyring/keyring \
--log-bin=mysql-bin --log-slave-updates --server-id=1 --gtid-mode=ON --enforce-gtid-consistency --binlog-format=row --core-file --basedir=/home/shahriyar.rzaev/XB_TEST/server_dir/PS131117-percona-server-5.7.19-17-linux-x86_64 \
--tmpdir=/home/shahriyar.rzaev/XB_TEST/server_dir/PS131117-percona-server-5.7.19-17-linux-x86_64/data \
--datadir=/home/shahriyar.rzaev/XB_TEST/server_dir/PS131117-percona-server-5.7.19-17-linux-x86_64/data \
--plugin-load-add=tokudb=ha_tokudb.so …
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Where does my MySQL configuration variable value come from ?

As you may already know, there are many different places where a MySQL configuration variables can be initialized.

In MySQL 8.0, we added in performance_schema a table allowing you to easily find where a variable was defined.

Let’s check this in action with max_connections for example.

I started mysqld and now I check the value of max_connections:

mysql> show global variables like 'max_connections';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 151   |
+-----------------+-------+

We can also use the performance.schema table called variables_info to get some more details about it:

mysql> SELECT t1.*, VARIABLE_VALUE 
       FROM performance_schema.variables_info t1 
       JOIN performance_schema.global_variables t2 
         ON t2.VARIABLE_NAME=t1.VARIABLE_NAME
      WHERE …
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What’s New in MariaDB Connector/J 2.2 and 1.7

What’s New in MariaDB Connector/J 2.2 and 1.7 diego Dupin Tue, 11/14/2017 - 05:56

We are pleased to announce the general availability (GA) of MariaDB Connector/J 2.2 and 1.7, the newest versions of MariaDB Connector/J. 

As both new versions are fully compatible to their corresponding latest maintenance releases to support Java 6/7 and Java 8+, version 2.1.2 and 1.6.5 are the last maintenance releases for 2.1 and 1.6.

New enhancements include:

Pool Datasource

There are now two different Datasources implementations:

  • MariaDbDataSource: The existing basic implementation. A new connection each time the getConnection() method is called.
  • MariaDbPoolDataSource: Connection pooling implementation. MariaDB Driver will keep a pool of connections and borrow connections when asked for it.

Good framework already exists that can accomplish …

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Webinar: What’s New in Monyog & Roadmap Update

Join Shree Nair, Product Manager at Webyog, as he demonstrates the new features introduced in the recent Monyog releases and rolls out the roadmap for the upcoming releases.

Date & Time: Tuesday, Nov 21, 2017 at 11:00 am EDT / 5:00 pm CET.

Register Now!

What to expect from the webinar?

You will have a better understanding of how to use the new features per your use-case. You will learn about the product roadmap. You can take part in Q&A session and submit your feature requests too.

If you can’t attend this webinar live, register anyway and we’ll send you a link to the recording.

You can download a free trial of Monyog …

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