This blog gives some background to the decisions made when designing the
storage engine NDB Cluster used in MySQL Cluster around how to support
real-time requirements (or as I sometime refer to it, predictable response
time requirements).

Requirement analysisWhen analysing the requirements for NDB Cluster based on its usage in telecom
databases two things were important. The first requirement is that we need to
be able to respond to queries within a few milliseconds (today even down to
tens of microseconds). The second requirement is that we need to do this while
at the same time supporting a mix of simple traffic queries combined with a
number of more complex queries running at the same time.

The first requirement was the main requirement that led to NDB Cluster using a
main memory storage model with durability on disk using a REDO log and
various …

The swedish research institute, SICS, have worked hard for a few years on
developing a scalable and a highly available Hadoop implementation using
MySQL Cluster to store the metadata. In particular they have focused on the
Hadoop file system (HDFS) and the YARN. Using features of MySQL
Cluster 7.5 they were able to achieve linear scaling in number of name
nodes as well as in number of NDB data nodes to the number of nodes
available for the experiment (72 machines). Read the press release from
SICS here

The existing metadata layer of HDFS is based on a single Java server
that acts as name node in HDFS. There are implementations to ensure
that this metadata layer have HA by using a backup name node and to
use ZooKeeper for heartbeats and a number of …

I have been fairly quiet on my blog for some time. We've been very busy
developing new features for MySQL Cluster 7.5 and ensuring that the
quality is improved even further.

We're now very pleased to release a new version of MySQL Cluster.

MySQL Cluster 7.5 contains a number of new things that makes MySQL
Cluster even better.
1) You can declare a table as a READ_BACKUP table. This means that
the updating transactions will receive the commit acknowledge
a little bit later to ensure that we can always use any of the
replicas for reading. We will use the nearest replica for
committed reads, for locking reads we will still use the primary
replica to avoid deadlocks.

For applications that are mostly read-focused one can make it easier
to set this variable by setting the ndb-read-backup config variable
to 1 in the MySQL Server …

My first post in this series caused quite an active discussion on Facebook. Readers correctly noted some mistakes in dates and missing names in the list. I've corrected some of the mistakes already and will correct some others later. What was also noted is that initially support for MySQL was provided by developers (this is really important, we'll get back to this later), and of them many had never even got a title of Support engineer. Of those who had not I listed only Monty...

I just want to explain why I made these mistakes and/or why I (intentionally) had not listed developers etc. First of all, I based my post on my memories (so I could be also wrong about start dates and many details) and that's why I could not …

I'd like to devote this long weekend post, the first in a new series, to my current and former colleagues who once worked or still work in a company that provided public MySQL Support service and had a job role of MySQL Support engineer. The list of companies include MySQL AB/Inc ("good old MySQL"), Sun, Oracle, Percona, MariaDB, FromDual, maybe more (I named only those that surely provided or provides MySQL Support for customers outside of the company).

This is not the first time that I write about "people of MySQL", in a wider sense "those who contribute to MySQL Community". Last time it was about …

Here’s a way to detect the sql query causing a lock or a session to fail, and also to identify the o.s.pid if need be (btw, no rocket science). “a” way.. I’m sure there are many others, so feel free to suggest, please.

So, we’re using MCM, and have created a MySQL Cluster like mentioned in the cluster intro session (in Spanish I’m afraid), using 7.4.6, which comes with 5.6.24.

With the env up and running, set up a schema, some data and run a few queries:

mysql> create database world;
mysql> use world;
Database changed
mysql> source world_ndb.sql

(world_ndb.sql, as you might guess, is the world_innodb tables script, with a little adjustment as to which storage engine to be used.)

Once created, let’s lock things up in Cluster:

mysql -uroot -h127.0.0.1 -P3306
mysql> use test; …

MySQL Cluster: El ‘qué’ y el ‘cómo’.

Para aquellos que encuentran mucho sobre MySQL en Inglés pero poco en Español: mi pequeña aportación.
En el enlace tenéis información sobre qué es MySQL Cluster y cómo funciona. Incluso con ejemplos técnicos para romper las barreras y ayudar a simplificarlo (espero).

¡A disfrutar!

January 30, 2015 By Severalnines

Thanks to everyone who participated in these two sessions this week! Please see below for details on next week’s follow up session 'Performance Tuning for HAProxy & MySQL'.

The topics covered this week included: 

• What is HAProxy?
• SQL Load balancing for MySQL
• Failure detection using MySQL health checks
• High Availability with Keepalived and Virtual IP
• Use cases: MySQL/MariaDB Galera Cluster, MySQL NDB …

Thanks to everyone who attended and participated in last week’s webinar on 'Galera Cluster for MySQL vs MySQL (NDB) Cluster: A High Level Comparison'. If you missed the sessions or would like to watch the webinar again & browse through the slides, they are now available online.

In this webinar, Severalnines VP of Products, Alex Yu, who was part of the team at Ericsson who originally developed the NDB storage engine in 2001, gave an overview of the two clustering architectures and discussed their respective strengths and weaknesses: 

1. MySQL Cluster architecture: strengths and limitations
2. Galera Architecture: strengths and limitations
3. Deployment scenarios
4. Data migration
5. Read and write workloads (Optimistic/pessimistic locking)
6. WAN/Geographical replication
7. Schema changes
8. Management and monitoring …

While working with MySQL Cluster, i was looking for a monitoring framework for the cluster.

i came across a library @ https://launchpad.net/ndb-bindings – which had java and other connectors to NDB, the library was a wrapper of the existing C++ NDB Api.

This library allowed me to connect to the management node , get the state of the cluster and get real time notifications about heartbeat misses/node disconnections.

The library error-ed out on some conditions, with a small fix, it can work with MySQL Cluster 7.3.

https://github.com/jaihind213/mysql-cluster-ndb-bindings

I have listed down steps for compilation and running a sample program at github