Thanks to everyone who joined us last week for this live session on backup strategies for MySQL and Galera clusters led by Krzysztof Książek, Senior Support Engineer at Severalnines. The replay and slides to the webinar are now available to watch and read online via the links below.

Watch the replay

Become a MySQL DBA - webinar series: Deciding on a relevant backup solution from Severalnines AB   Read the slides

Become a MySQL DBA - slides: Deciding on a relevant backup solution from …

Addition of support for Apache Cassandra and DataStax Enterprise extends Pythian’s leadership in extreme-scale database deployments and big data services

OTTAWA, Canada – July 8, 2015 – Pythian, a global IT services company specializing in helping companies leverage disruptive technologies to optimize revenue-generating systems, today announced the general availability of its consulting and follow-the-sun managed services support for both Apache™ Cassandra™ and DataStax®, the company that delivers Apache Cassandra to the enterprise. Cassandra is an open-source, distributed database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure.

Pythian leverages an extensive suite of managed services, tools, and database experience to get organizations up and running in their Cassandra and …

There is nothing more to be said:

SELECT
gen.TABLE_SCHEMA
, gen.TABLE_NAME
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
) as COLUMN_NUM
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY != ""
) as INDEX_NUM_ALL
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "PRI"
) as INDEX_NUM_PRI
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "UNI"
) as INDEX_NUM_UNI
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "MUL"
) as INDEX_NUM_MUL

from …

MySQL replication has been available for years, and even though a number of new clustering technologies showed up recently, replication is still very common among MySQL users. It is understandable as replication is a reliable way of moving your data between MySQL instances. Even if you use Galera or NDB cluster, you still may have to rely on MySQL replication to distribute your databases across WAN.

In this blog post we’d like to discuss one of the most common operations DBA has to handle - replication topology changes and planned failover. 

This is the fifth installment in the ‘Become a MySQL DBA’ blog series, and discusses one of the most common operations a DBA has to handle - replication topology changes and planned failover. Our previous posts in the DBA series include Schema Changes, …

Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies”

In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered:

1. GDB Introduction
2. Backtrace, Stack trace
3. Frames
4. Commands & Logging
5. Variables
6. Library dependencies
7. c++filt
8. Handy references
– GDB Cheat sheet (page #2): https://goo.gl/rrmB9i
– From Crash to testcase: https://goo.gl/3aSvVW

Also expands on live debugging & more. In HD quality (set your player to 720p!)

The post MySQL QA Episode 3: How to use the debugging tool GDB appeared first on …

As the old management adage goes, “You can’t manage what you don’t measure.” In the fast-paced world of IT, this more accurately translates to, “You can’t improve what you don’t measure.”

When it comes to your database, a continuous monitoring system provides the foundation for progress: metrics. Without a monitoring system, it’s impossible to determine whether changes actually impact the system’s performance, availability, and functionality.

Think of it like a science experiment: You wouldn’t trust research that didn’t measure the results. So why would you settle for faulty database metrics? Read the full article here.

Object-relational mapping is common in most modern web frameworks such as Ruby on Rails. For the developer APIs, the ORM provides simplified interaction with the database and a productivity boost. However, the layer of abstraction the ORM provides can hide how the database is being queried. If you’re not paying attention, these generated queries can have a negative effect on your database’s health and performance.

Join Owen August 4th at 2 PM EST (6 PM GMT), as he discusses ways common Rails ORMs can abuse various databases and how VividCortex can be used to discover them. He will show the before and after effects on database performance, using VividCortex to measure results.

This webinar is useful for any developer or sysadmin working with Ruby On Rails. While we use our product to detect problems, it will be helpful even if you do not currently use VividCortex.

About the Presenter

Owen Zanzal is a developer …

I noticed that in the latest release of Percona XtraDB Cluster (PXC), the behavior of wsrep_RSU_method changed somewhat.  Prior to this release, the variable was GLOBAL only, meaning to use it you would:

mysql> set GLOBAL wsrep_RSU_method='RSU';
mysql> ALTER TABLE ...
mysql> set GLOBAL wsrep_RSU_method='TOI';

This had the (possibly negative) side-effect that ALL DDL’s issued on this node would be affected by the setting while in RSU mode.

So, in this latest release, this variable was made to also have a SESSION value, while retaining GLOBAL as well. This has a couple of side-effects that are common to MySQL variables that are both GLOBAL and SESSION:

• The SESSION copy is made from whatever the GLOBAL’s value is when a new connection (session) is …

In the MySQL team we are currently considering a proposal to deprecate a number of alternative syntax uses with the INSERT and REPLACE commands. To provide examples:

CREATE TABLE `city` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `Name` char(35) NOT NULL DEFAULT '',
  `CountryCode` char(3) NOT NULL DEFAULT '',
  `District` char(20) NOT NULL DEFAULT '',
  `Population` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`),
  KEY `CountryCode` (`CountryCode`),
  CONSTRAINT `city_ibfk_1` FOREIGN KEY (`CountryCode`) REFERENCES `Country` (`Code`)
) ENGINE=InnoDB AUTO_INCREMENT=4080 DEFAULT CHARSET=latin1;

INSERT INTO city SET
 Name='NewCity', CountryCode='CAN',District='MyDistrict',Population=1234;

INSERT INTO city (Name,CountryCode,District,Population) VALUE
 ('NewCity2', 'CAN', 'MyDistrict', 1234);

INSERT city (Name,CountryCode,District,Population) VALUES
 ('NewCity3', 'CAN', 'MyDistrict', 1234);
 
REPLACE INTO city (Name,CountryCode,District,Population) VALUE …

Galera Cluster has the ability to add new nodes to the cluster by handling internally the transfer of the entire dataset to the new node. The same procedure, called State Snapshot Transfer (SST), applies to nodes that are rejoining the cluster after being down for a longer period of time.

A lot of operations happen during SST and there are various things that could go wrong. This article describes how to configure our server optimally for SST and how to debug any issues that arise.

The Basics

Let’s first consider all the items that play a role in the preparation and configuration of SST.

Selecting an SST Method

Galera Cluster supports several different methods for performing SST so, before adding a new node, it is worth examining the alternatives:

• rsync is the default method and requires the least amount of setup. Its disadvantage is that the donor node remains locked for all …