As a MySQL support engineer, I see this so often, that I felt it could help to write a post about it.

Customers contact us to ask about replication lag – ie, a slave is very far behind the master, and not catching up. (“Very far” meaning hours behind.)

The most common reason I encounter is databases having InnoDB tables without explicit primary keys. Especially if you are using row-based replication (“RBR”), you want explicit primary keys on all your tables. Otherwise, MySQL will scan the entire table for each row that is updated. (See bug 53375 . )  Maybe I’m a relational purist, but why would you want to have tables without explicit primary keys, anyway?  (On the other, less-purist, hand, for performance reasons, sometimes a short surrogate PK may be preferred to a lengthy logical one. )

The other common reason is that the slave …

I have released MySQL-Sandbox 3.1.01, which is the first release after the move to GitHub. While the changes are not so spectacular (it's a minor release, with mostly bug fixes), I am pleased to see that the move has started producing collaboration. Two of the changes were provided by Daniël van Eeden and Mark Leith, who have scratched some of their own itches by providing useful patches.

All in all, this period of working with GitHub has been liberating. Although Bazaar plays with the same principles of git, it lacks most of the tools and the know-how which characterizes git. Add to this that also my team has moved Tungsten Replicator …

I was recently downloading and trying to run a MySQL docker image  which worked just fine on top of a Hyper-V based Ubuntu 14.04 LTS. Don’t worry, this is still Entity Framework Code-First migration article with Visual Studio 2015 and MySQL 5.6.27 (latest as of today). I setup a Docker MySQL Image on my Ubuntu based Docker host. I was thinking what could be a best way to test this instance out with .NET than testing it with our good friend Entity Framework Code-First migration. This is really going to hit the MySQL instance hard by creating DB on its own and creating all the Model Tables on its own with little or no involvement of MYSQL DDL /DMLs. Prerequisites : – To start using Entity Framework 6 and Visual Studio 2015 is necessary to install

• …

Currently we have one database cluster with 15 different schemas – these schemas could be either schemas which contain “real” data, or just schemas with metadata.

I guess the next evolutionary step of our database stack would be to split up the database cluster vertically along these schemas. All the data schemas should be moved to standalone mysql instances, and put the metadata schemas next to them. This also could be a good project for prepare to move a certain part of database for example to a cloud provider while other parts are still kept on bare metal.

I started wondering what could be the best way to split MySQL instances in a single hardware. I have the following ideas:

• Hack init scripts to start different instances on different ports (and log directories, data directories, config files too)
• Use mysqld_multi
• Use MySQL Sandbox
• Use docker

The first …

AWS CloudFormation now supports Amazon Aurora!

Announcement: https://forums.aws.amazon.com/ann.jspa?annID=3286

Documentation:

http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbcluster.html

Amazon Aurora is a MySQL-compatible, relational database engine that combines the speed and availability of high-end commercial databases with the simplicity and cost-effectiveness of open source databases. https://aws.amazon.com/rds/aurora/

AWS CloudFormation gives developers and systems administrators an easy way to create and manage a collection of related AWS resources, provisioning and updating them in an orderly and …

This Log Buffer Edition finds and publishes blog posts from Oracle, SQL Server and MySQL.

Oracle:

• SCRIPT execution errors when creating a DBaaS instance with local and cloud backups.
• Designing Surrogate vs Natural Keys with Oracle SQL Developer.
• EBS General Ledger – Accounting Hub Reporting Cloud Service.
• Oracle Database Standard Edition 2 is available.
• Disable “Build After Save at …

Percona recently open sourced TokuBackup, a library that may be used to take a snapshot of a set of files while these files are being changed by a running application like MySQL or MongoDB.  Making TokuBackup open source allows a larger set of users to improve and extend the software.  This blog describes how the Address Sanitizer and Thread Sanitizer found bugs in the TokuBackup library.

The TokuBackup library is used by Percona Server for MySQL and …

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 …

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

…

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: