Percona Live Europe is now more than a week away. l left Amsterdam with a positive thought: it has been the best European event for MySQL so far. Maybe the reason is that I saw the attendance increasing, or maybe it was the quality of the talks, or because I heard others making the same comment, and I also saw a reinvigorated MySQL ecosystem.
There are three main aspects I want to highlight.

1. MySQL 5.7 and the strong presence of the Oracle/MySQL team
There have been good talks and keynotes on MySQL 5.7. It is a sign of the strong commitment of Oracle towards MySQL. I think there is an even more important point. The most interesting features in 5.7 and the projects still in MySQL Labs derive or are in some way inspired by features available from other vendors. Some examples:

• The JSON datatype from …

MySQL Group Replication plugin is in labs.mysql.com and is available for EL6 x86_64 version Linux. But most of us have Ubuntu desktops where it should be easier to test this new thing, especially with MySQL Sandbox. After getting source code we should have compile this plugin with MySQL from source. So let’s begin. Extract both mysql group replication archive and mysql source archive:

sh@shrzayev:~/Sandboxes$ ls -l
total 650732
drwxr-xr-x 34 sh sh      4096 İyl 20 17:25 mysql-5.7.8-rc
-rw-rw-r--  1 sh sh  49762480 Avq 20 16:19 mysql-5.7.8-rc.tar.gz
drwxrwxr-x  3 sh sh      4096 Sen 28 12:08 mysql-group-replication-0.5.0-dmr
-rw-rw-r--  1 sh sh    251687 Sen 28 11:57 mysql-group-replication-0.5.0-labs.tar.gz

You will have 2 directories as above. Then, go to mysql-group-replication folder:

sh@shrzayev:~/Sandboxes$ cd mysql-group-replication-0.5.0-dmr/
sh@shrzayev:~/Sandboxes/mysql-group-replication-0.5.0-dmr$ …

see below.

You should install “libhiredis-dev” before run ./configure.
Trye

Introduction

The purpose of this test is to benchmark MySQL 5.6 performance on hardware with Haswell CPUs, SSDs and PCIe Flash storage devices.

Background

Software

• SysBench OLTP workload installed on the database machine
  
• MySQL 5.6.24 distribution from Percona
  
• jemalloc used for MySQL Server and Sysbench test client
  
• Charts are plotted using MySQL Performance Analyzer

Method

• Data and software on server was wiped out post every test run.
  
• Predefined number of tables - 16 or 64
  
• Predefined size of rows - 20M per table
  

Tests
Read Only
Read Write
Concurrencies vary from 1 to 512 with incremental increase
EXT4 vs XFS

…

The sort buffer, which is controlled by the sort_buffer_size setting, is probably one of the most-discussed MySQL settings. Interestingly, in many cases it has a lot less potential to help performance than to hurt it, so configuring it is often about avoiding trouble rather than gaining a lot of performance.

The variable controls the size of a buffer that’s created whenever MySQL has to sort rows. It is per-query, meaning each query gets its own buffer, and it’s allocated to its full size, not as-much-as-needed. This makes large settings potentially dangerous.

The worst abuse of this variable we’ve seen came from a server that was tuned with a script. The script relied on a naive formula that looked at a simplistic ratio of some server variables. Due to the server’s workload the script was never satisfied and continually suggested increasing this variable, which eventually was set to 1GB. The effect was that …

Capturing data is a critical part of performing a query analysis, or even just to have an idea of what’s going on inside the database.

There are several known ways to achieve this. For example:

• Enable the General Log
• Use the Slow Log with long_query_time = 0
• Capture packets that go to MySQL from the network stream using TCPDUMP 
• Use the pt-query-digest with the –processlist parameter

However, these methods can add significant overhead and might even have negative performance consequences, such as:

An index is a data structure that sorts a number of records on one or more fields, and speeds up data retrieval. This is to avoid scanning through the disk blocks that a table spans, when searching through the database. So, what kind of indexes are available in MySQL and how do we use them to get the most performance? This will be the topic for this blog. 

This is the twelfth installment in the ‘Become a MySQL DBA’ blog series. Our previous posts in the DBA series include Deep Dive pt-query-digest, Analyzing SQL Workload with pt-query-digest, …

I'm very excited to announce that some of my content is featured in the PHP Learning Path from O'Reilly. The Learning Paths are a good way to buy a bundle of content from different people on related topics, and the introductory pricing is always a good deal! Their newest offering is the PHP Learning Path, which has a video course on PHP and MySQL, my intermediate PHP Video course (they wouldn't let me call it "all the things Lorna thinks PHP developers need to know" unfortunately!) and also my video course Git for Web Developers which has a bunch of PHP in it as well as my best git tips and tricks.

I think it's a pretty well-rounded collection and it's only $99 for a couple of weeks, so get the PHP Learning Path here and let me know what you think?

…

When changing a MySQL table or column to a new character set that uses more bytes than the old character set, you need to first check if any schema changes are needed to accomodate the change. For example, changing character sets from latin1 to utf8 is an increase from 1 to 3 bytes, and changing from utf8 to utf8mb4 is an increase from 3 to 4 bytes. The MySQL reference manual has a helpful page with some details on this, but I want to add some examples to show how this schema prep can be accomplished.

There are three different types of length limits to take into consideration:

• Index
• Column
• Row

In this post I will focus on index length limits, and I'll save columns and rows for future posts. Read on for details.

Index Length Limits

The specific limits depend on …