In April, I wrote a blog post introducing the new InnoDB virtual column and effective functional index work for the JSON lab release. Now the feature is officially in MySQL 5.7.8. It’s worth revisiting the topic again in order to write about what is in the 5.7 Release Candidate, along with providing some additional examples.…

Recent changes to support better security by increasing strength of Diffie-Hellman cipher suites from 512-bit to 2048-bit were introduced to MySQL Server 5.7. While this change enhances security, it is an aggressive change in that 2048-bit DH ciphers are not universally supported. This has become a problem specifically for Java users, as only Java 8 JRE (currently) supports DH ciphers greater than 1024 bits. Making the problem more acute, this change was back-ported from MySQL Server 5.7 to the recent 5.6.26 and 5.5.45 releases in response to a community bug report. This blog post will identify affected applications, existing workarounds, and our plans to provide a more …

My server is crashing… Now what?

This special episode in the MySQL QA Series is for customers or users experiencing a crash.

1. A crash?
   1. Cheat sheet: https://goo.gl/rrmB9i
   2. Sever install & crash. Note this is as a demonstration: do not action this on a production server!
      sudo yum install -y http://www.percona.com/downloads/percona-release/redhat/0.1-3/percona-release-0.1-3.noarch.rpm
      sudo yum install -y Percona-Server-client-56 Percona-Server-server-56
      sudo service mysql start
2. Gimme Stacks!
   1. Debug info packages (can be executed on a production system, but do match your 5.5, 5.6 or 5.7 version correctly)
      sudo yum install -y Percona-Server-56-debuginfo
   …

I’m excited to be at LinuxCon North America in Seattle next week (August 17-19 2015). I’ve spoken at many LinuxCon events, and this one won’t be any different. Part of the appeal of the conference is being able to visit a new place every year.

MariaDB Corporation will have a booth, so you’ll always be able to see friendly Rod Allen camped there. In between talks and meetings, there will also be Max Mether and quite possibly all the other folk that live in Seattle (Kolbe Kegel, Patrick Crews, Gerry Narvaja).

For those in the database space, don’t forget to come attend some of our talks (represented by …

The latest MySQL Sandbox, version 3.0.66 is out. It has a few new features (as always, when I find myself doing the same thing many times, I script it) and improved support for latest releases of MySQL. You can now install, among other versions, MySQL 5.7.8 and MariaDB 10.1.x

Some notable additions in this release are in the scripts that are created and customized for each sandbox. There are many of them and when one more arrives, it's easy to overlook it. So, here are the new arrivals.



./show_binlog
When I am troubleshooting replication behavior, I often need to inspect the latest binary log. The sandbox has a shortcut that gives me the right version of mysqlbinlog for the deployment:

An old story that is not yet solve.

Why this article.

Some time ago I had open a bug report to codership through Seppo.

The report was about the delay existing in executing data load with FK. (https://bugs.launchpad.net/codership-mysql/+bug/1323765).

The delay I was reporting at that time were such to scare me a lot, but I know talking with Alex and Seppo that they were aware of the need to optimize the approach an some work was on going.

After some time I had done the test again with newer version of PXC and Galera library.

This article is describing what I have found, in the hope that share information is still worth something, nothing less nothing more.

The tests

Tests had being run on a VM with 8 cores 16GB RAM RAID10 (6 spindle 10KRPM).

I have run 4 types …

MariaDB 10.1.6 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.1.6/

This is the 4th beta, and 7th overall, release of MariaDB 10.1. There were not many major changes in this release, but a few notable items, as well as many overall bugs fixed (I counted 156, down ~50% from 10.1.5).

Since it’s beta, I’ll only cover the major changes and additions, and omit covering general bug fixes (feel free to browse them all here).

To me, these are the highlights:

• RESET_MASTER is extended with TO # clause which allows one to specify the number of the first binary log. (MDEV-8469)
• Added support for …

MySQL 5.6.26 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.

For this release, there are 3 “Functionality Added or Changed” items, 1 “Security Fix”, and 36 other bug fixes.

Out of those other 36 bugs, 13 are InnoDB, 1 Partitioning, 3 Replication, and 19 misc. (including 3 potentially crashing bug fixes, and 1 performance-related fix) Here are the ones of note:

• Functionality Added/Changed: Replication: When using a multi-threaded slave, each worker thread has its own queue of transactions to process. In previous MySQL versions, STOP SLAVE waited for all workers to process their entire queue. This logic has been changed so that STOP SLAVE first finds the newest transaction that was committed by any worker thread. Then, it waits for all workers to complete …

MySQL 5.5.45 was recently released (it is the latest MySQL 5.5, is GA), and is available for download here:

http://dev.mysql.com/downloads/mysql/5.5.html

This release, similar to the last 5.5 release, is mostly uneventful.

There were 0 “Functionality Added or Changed” items this time, 1 “Security Fix”, and just 9 bugs overall fixed.

Out of the 9 bugs, there were 3 InnoDB bugs, 1 security-related bug, and 1 potential crashing bug. Here are the ones worth noting:

• InnoDB: An index record was not found on rollback due to inconsistencies in the purge_node_t structure.
• InnoDB: An assertion was raised when InnoDB attempted to dereference a NULL foreign key object.
• InnoDB: On Unix-like platforms, os_file_create_simple_no_error_handling_func and …

Introduction

A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table. The purpose of the foreign key is to identify a particular row of the referenced table. Therefore, it is required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value). This is called a referential integrity constraint between the two tables. Because violations of these constraints can be the source of many database problems, most database management systems provide mechanisms to ensure that every non-null foreign key corresponds to a row of the referenced table. Consider following simple example:

create table parent (
    id int not null primary key,
    name char(80)
) …