MySQL NDB Cluster uses row level locks instead of a single shared commit lock in order to prevent inconsistency in simultaneous distributed transactions. This gives NDB a great advantage over all other MySQL clustering solutions and is one reason behind cluster’s unmatched ability to scale both reads and writes. 
NDB is a transactional data store. The lowest and only isolation level available in NDB is Read Committed. There are no dirty reads in NDB and only committed rows can be read by other transactions. 
All write transactions in NDB will result in exclusive row locks of all individual rows changed during the transaction. Any other transaction is allowed to read any committed row independent of their lock status. Reads are lock-free reads.
The great advantage is that committed reads in NDB never block during writes to the same data and always the latest committed changes are read. A select doesn't block concurrent …

This is Part #2 of the MySQL Master Replication Crash Safety series.  In the previous post, we explored the consequence of reducing durability on masters with slaves using legacy file+position replication.  The consequences are data inconsistencies with a clear warning sign: the slaves stop replicating and report an error.  In this post, we extend our understanding of the impact of running a

MySQL High Availability. Shutterstock.com[/caption] In this article, we'll look at an example of an on-premises, geographically distributed MySQL high availability solution. It's part of a longer series on some high availability reference architecture solutions over geographically distributed areas. Part 1: Reference Architecture(s) for High Availability Solutions in Geographic Distributed Scenarios: Why Should I Care? Percona consulting's main aim is to identify simple solutions to complex problems. We try to focus on identifying the right tool, a more efficient solution, and what can be done to make our customers' lives easier. We believe in doing the work once, doing it well and have more time afterward for other aspects of life. In our journey, we often receive …

Let's talk about MySQL high availability (HA) and synchronous replication once more.
It's part of a longer series on some high availability reference architecture solutions over geographically distributed areas.
Part 1: Reference Architecture(s) for High Availability Solutions in Geographic Distributed Scenarios: Why Should I Care?
Part 2: MySQL High Availability On-Premises: A Geographically Distributed Scenario

The Problem

A question I often get from customers is: How do I achieve high availability in case if I need to spread my data in different, distant locations? Can I use …

Migrating to Amazon Aurora. Shutterstock.com

In this Checklist for Success series, we will discuss reducing unknowns when hosting in the cloud using and migrating to Amazon Aurora. These tips might also apply to other database as a service (DBaaS) offerings.

While DBaaS encapsulates a lot of the moving pieces, it also means relying on this approach for your long-term stability. This encapsulation is a two-edged sword that takes away your visibility into performance outside of the service layer.

Shine a Light on Bad Queries

Bad queries are one of the top offenders of downtime. Aurora doesn’t protect you against them. Performing a query review as part of a routine health check of your workload helps ensure that you do not miss looming issues. It also helps you predict the …

Implementing Galera Cluster on Amazon EC2  provides several advantages for companies. Multi-master clustering comes out of the box as a default in Galera. Users can read and write from any database providing fast local writes and reads. Galera handles conflicts automatically if your application is writing to the same row. Nodes can be added and deleted on the fly if you need more capacity and elasticity. New nodes can join automatically. In the case data center downtime Galera provides disaster recovery and Galera Cluster takes care of the split brain situation too. Automated failover and recovery allow the database to continually service the application transparently.

Meet the developers and experts of Galera Cluster in Amazon re:Invent Las Vegas 26-29 November. You can find us at Venetian hotel, booth number 738.

“Delayed replication” is one of the important features which were being supported in MySQL from 5.6 for a very long time. This induces an intentional lag in the slave, making it lag by the defined time interval.

For a long time this was not available with the RDS version of MySQL provided by AWS, Recently from the version 5.6.40, 5.722 and later versions this feature is available with all the regions.

I will give a small intro on Amazon RDS, Which is DBAAS provided by Amazon, where you will be given an end-point for all your DB operations and major of admin task of server and DB is taken care by Amazon, To know more you can view our presentation here

In this blog, I will demonstrate, how to have a delayed slave with Amazon RDS for MySQL

Note: If you are …

I love the new shell but the one thing I missed from the old shell was the ability to use a pager like more or less to throttle the output of the screen.  Low and behold the engineers have added paging in MySQL Shell 8.0.13!!

Turn Paging On
Things can scroll off the screen quickly and pagination programs keep the output to small chunks.  To pick the more program as you pagination program, simply enter \pager more or for less enter \pager less

See the first illustration

…

ProxySQL 1.4.12, released by ProxySQL, is now available for download in the Percona Repository along with an updated version of Percona’s proxysql-admin tool.

ProxySQL is a high-performance proxy, currently for MySQL and its forks (like Percona Server for MySQL and MariaDB). It acts as an intermediary for client requests seeking resources from the database. René Cannaò created ProxySQL for DBAs as a means of solving complex replication topology issues.

The ProxySQL 1.4.12 source and binary packages available at https://percona.com/downloads/proxysql …

In the last few months, I had to install Percona Server 5.7 (PS5.7) on Debian a few times.  I was regularly annoyed by apt-get -y install percona-server-server-5.7 prompting me for a password.  But that annoyance did not push me to investigate the subject in detail: it was always a quick manual fix and Googling did not lead to a straightforward solution.  However in the last days, I had to