Automatic failover for MySQL Replication has been subject to debate for many years.

Is it a good thing or a bad thing?

For those with long memory in the MySQL world, they might remember the GitHub outage in 2012 which was mainly caused by software taking the wrong decisions.

GitHub had then just migrated to a combo of MySQL Replication, Corosync, Pacemaker and Percona Replication Manager. PRM decided to do a failover after failing health checks on the master, which was overloaded during a schema migration. A new master was selected, but it performed poorly because of cold caches. The high query load from the busy site caused PRM heartbeats to fail again on the cold master, and PRM then triggered another failover …

I promised to do a pricing post on the Amazon RDS Aurora MySQL pricing, so here we go.  All pricing is noted in USD (we’ll explain why)

We compared pricing of equivalent EC2+EBS server instances, and verified our calculation model with Amazon’s own calculator and examples.  We use the pricing for Australia (Sydney data centre). Following are the relevant Amazon pricing pages from which we took the pricing numbers, formulae, and calculation examples:

• Amazon EC pricing (on demand)
• Amazon EBS pricing
• Amazon RDS Aurora pricing (on demand)
• Amazon AWS calculator tool …

In this blog post, I want to go over some of the day-to-day MySQL tools and methods DBAs use to analyze queries and visualize “what is going on?” I won’t be going into the nitty-gritty details of each of these tools, I just want to introduce you to them and show you what they look like so you will know what types of information they provide.

This isn’t a comprehensive list by any means but consider it a primer for those starting with MySQL and wanting to know what a query is going to do or is doing.

The two sides of query analysis are examining a query BEFORE you run it, and then analyzing what actually happened AFTER you run it.

Let’s start with the tools you can use to predict a query’s future.

In the beginning, there was EXPLAIN. The venerable EXPLAIN command has been with us a long time as a built-in MySQL utility statement. Its purpose is to explain that what the optimizer …

Percona announces the release of Percona Toolkit 3.0.7 on March 1, 2018.

Percona Toolkit is a collection of advanced open source command-line tools, developed and used by the Percona technical staff, that are engineered to perform a variety of MySQL®, MongoDB® and system tasks that are too difficult or complex to perform manually. With over 1,000,000 downloads, Percona Toolkit supports Percona Server for MySQL, MySQL, MariaDB®, Percona Server for MongoDB and MongoDB. Percona Toolkit, like all Percona software, is free and open source.

You can download packages from the website or install from official repositories.

This …

I’m pleased to announce that VividCortex now offers 99th percentile metrics to help understand latency outliers in a query workload. These metrics provide visibility beyond the average latency, help identify the worst outliers, and improve focus on the customer experience. They are offered for all of the databases we currently support when using On-Host monitoring.

What You'll See

Latency percentile metrics are one of our most popular feature requests, so we know this will make a lot of you very happy! We actually started collecting these metrics some time ago; you’ll have p99 latency metrics for the last couple of months if you look back at your historical metrics. These metrics are captured globally for an environment, per-query, per-database, per-user, per-verb, per-caller and per-custom-query-tag.

Why Did We Choose to Implement This? 

It is extremely useful for a lot of reasons. Averages can be …

MySQL 8.0 comes with improved defaults, aiming at the best out of the box experience possible. Here we describe the changes and why they are made.

Introduction

Generally speaking, a good default is “the best choice for most users, most of the time”.…

In our last blog, we had a look at MySQL 8 and mentioned new features available here. However, some of those features are already in MariaDB and have been for a while. We will here compare database roles in both server dialects.

The Purpose of Database Roles

It’s common for numerous users within an organization to share the same database privileges. A role bundles a number of privileges together so that the DBA can set the privileges for a group of users all at once, rather than having to set each user’s privileges individually.  

With shared applications, it is not uncommon for multiple users to share the same user account. The drawback to this arrangement is that there is no way to see which actual user was responsible for which action.

Roles make managing this much easier. For example, there …

In this article, 1st of a MySQL 5.7 Security series, we will see how to enforce Strong Passwords with Password Validation Plugin when using MySQL 5.7.

Authentication with ID and password is a very simple and common (because it’s simple) way to secure the access to a resource, however the password can be the weak point of this system. In order to increase the security level, you can required that your user passwords meet certain minimal security requirements, using the MySQL Password validation plugin!

MySQL 8.0 will be GA soon (just my assumption: Oracle doesn't tell me anything about its release plans) and it's time to think about having a look at it.
If this is your first try of MySQL 8, get prepared for several impacting differences from previous versions.

In this article I won't tell you what you can do with MySQL 8: there is plenty of material about this, including in this very blog. I will instead concentrate on differences from previous versions that users need to know if they want to avoid surprises.

Data Directory

Let's start with an observation of the data directory.
After a standard installation, without any additional options, I see the following:

Files that I expected to see

auto.cnf
ib_buffer_pool
ib_logfile0
ib_logfile1
ibdata1
ibtmp1
(dir) mysql
(dir) …

 Last_SQL_Error: Could not execute <Update/insert/delete>_rows event on table <dbname>.<tablename>; Can’t find record in ‘<tablename>’, Error_code: 1032; handler error HA_ERR_END_OF_FILE; the event’s master log <master binary log file name>, end_log_pos <master log file position>

This is one of the error for MySQL Replication when MASTER and SLAVE replica not in sync. The Reason for replication getting out of sync due to various reasons. But the common cause is particular table row or data not matched/missing on the slave while applying transaction received from MASTER. This transaction can be insert/update/delete type.

In this blog post will discuss support for MEMORY storage engine table with MySQL Replication and few examples with a possible solution. As per official MySQL DOC, …