In this blog we are going to share my recent experience with an issue which we faced during migration between two Ubuntu servers.

The activity was pretty simple, the client had bought a new machine with enhanced memory and faster disk, so the data has to be transferred to the new server and live MySQL replication has to be configured between the old and the new server.

For the hot and live data transfer we used xtrabackup’s stream method, the data transfer happened smoothly without any issue.

Everything was set and we had applied the log and followed the normal procedure to change the ownership of datadir to “mysql” and all the entries in the my.cnf were double checked.

When we intended to start mysql, the service didn’t come up instead we had a weird error as below.

MySQL Error:
——————

2016-08-31 22:35:27 9938 [ERROR] InnoDB: ./ibdata1 can't be opened in …

There was a bold announcement during the MySQL Keynote at Oracle Open World. A new product that will mix up with the existing GA server, called MySQL InnoDB Cluster. This is an evolution of MySQL group replication, which has been in the labs for long time, and the MySQL shell, which was introduced as a side feature last April. The boldness I mentioned before is on account of wanting to add to a GA server something that was defined as release candidate despite never having been out of the labs. The product is interesting as it promises to be a quick and painless cluster deployment, with built-in high availability and scalability.

…

What is InnoDB Cluster?

Hot off of Oracle Open World 2016 is the lab release of MySQL’s InnoDB Cluster.

InnoDB Cluster uses the Group Replication plugin to allow for virtually synchronous replication, while also providing a MySQL Router that is aware of the cluster state. By connecting your application to the router, your application will be able to withstand failover of any node participating in the cluster.

InnoDB Cluster also provides a new MySQL Shell to interact with the cluster commands.

MySQL’s server team gives us a very good hands-on tutorial if you’re interested in getting …

This blog post highlights a video on how to use regular expressions.

It’s been a while since I did the MySQL QA and Bash Training Series. The 13 episodes were quite enjoyable to make, and a lot of people watched the video’s and provided great feedback.

In today’s new video, I’d like to briefly go over regular expressions. The session will cover the basics of regular expressions, and then some. I’ll follow up later with a more advanced regex session too.

Regular expressions are very versatile, and once you know how to use them – especially as a script developer or software coder – you will return to them again and again. Enjoy!

Presented …

Now that MySQL 8.0 has been revealed, it's time to take a deep look at replication features in the latest releases, and review its overall design.

Server UUID vs Server-ID

At the beginning of replication, there was the server_id variable that identified uniquely a node in a replication system. The variable is still here, but in MySQL 5.6 it was joined by another value, which is created during the server initialisation, regardless of its involvement in a replication system. The server_uuid is a string of hexadecimal characters that is the basis for global transaction identifiers:

select @@server_id, @@server_uuid;
+-------------+--------------------------------------+
| @@server_id | @@server_uuid                        |
+-------------+--------------------------------------+ …

I found a useful tool named sniffer to help us analyze network packages (this tool can capture packages on specific port)

I use sniffer to analyze mysql and redis packages (translate these packages to normal queries)

#./vc-redis-sniffer –help

vc-redis-sniffer is a utility from VividCortex to monitor query activity and write results to a file.
See --license for the terms governing your usage of this program.

  -binding="[::]:6379"         This is a list of comma separated bind strings as seen in /proc/net/tcp
  -help="false"                Show this usage message
  -license="false"             Print the usage terms of this program
  -output=""                   Filepath to output queries to. Defaults to stdout if none specified.
  -show-database="false"       Include a 'USE `database`' for every statement. Supersedes show-database-changes.
  -show-database-changes="false" …

A customer showed that a particular client reported a less-than-helpful error message when it tried to display some meta-data about a table.

I couldn’t repeat the behavior with just a copy of the schema, so I suspected it was because of the size of data in the customer’s server – somebody had used an int where they needed a long.

The customer’s data was quite large – many hundreds of GB – more than I could easily whip up on my laptop to test. But, I didn’t really need all that data, or even any data at all; I just needed MySQL to pretend it had all that data. Specifically, I needed information_schema to report a large data_length.

Enter Rewriter, the query rewrite plugin that ships …

In this blog post we will present a first look at the performance of Group Replication (GR), now that the RC is out. The goal is to provide some insight on the throughput, latency and scalability one can expect in a modern computing infrastructure, using GR in single- and multi-master configurations, but mostly focused on single-master.…

It is a common auditing requirement to log user connection events, including whether or not authentication was successful.
There are a number of alternatives available for MySQL, but unfortunately there is no built-in functionality at the time of this writing. In this post we will discuss auditing MySQL users with McAfee plugin, which is available under GPL Version 2 license.

Installation instructions

These apply to debian-based hosts, but instructions for red hat are similar.

1. Download latest plugin release from github.

At the time of this post for MySQL 5.5 you can get:

wget https://bintray.com/mcafee/mysql-audit-plugin/download_file?file_path=1.0.9-release%2Faudit-plugin-mysql-5.5-1.0.9-585-linux-x86_64.zip

2. Decompress …

The MySQL development team just published a Labs release of the MySQL Server (available under “MySQL Server 8.0.0 Optimizer”).
A prominent feature of this release, which I developed, is [Recursive] Common Table Expressions, also known as

• [recursive] CTE,
• [recursive] subquery factoring,
• WITH [RECURSIVE] clause.

…