In July, I first wrote that we are currently working on a new data dictionary for MySQL. We have since shipped a labs release where you can try it out for yourself and then send us feedback!
Today, I wanted to write about our upgrade plan from the old data dictionary to the new data dictionary. Or more specifically, explain one of the nuances that we currently have with encoding characters that are not safe on all filesystems.
To quote from the MySQL manual:
For example, if a …
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Permalink: http://bit.ly/1rNFRsO
The stripped down stored procedure shown below will accept any
Data Manipulation Language statement as its parameter and
automatically log the statement and create table backup copies
before the statement is executed. The logging functionality is
similar to MySQL's binary log but exclusive to DML statements and
is useful for table data recovery operations, such as undoing the
last table data change or to revert databases back to a certain
point in time. All this is done exclusively using stored routines
(procedures and functions).
Its assumed that the databases and tables that will be used are
already formed to specific business requirements since DDL
statements will not be logged by the stored procedure. Though
logging of table data changes can also be achieved using
triggers, it is not practical to alter each and …
If you have a look on the last mysql 5.7.4 version or later you
will probably see that there are several security improvements.
The list of added security features and improvements can be seen
on the following page: http://dev.mysql.com/doc/refman/5.7/en/mysql-nutshell.html
There are three main improvements that are shortly described in
this blog:
1. Nonempty plugin column
2. Password lifetime policy
3. mysql_install_db secured
Nonempty plugin column
As of MySQL 5.7.2, the server requires account rows in the
mysql.user table to have a nonempty
plugin column value and disables accounts with an
empty value. The following error will occor when trying to
connect with user having empty plugin colum:
2014-11-30T10:41:04.943384Z …
Or how wsrep_on can bring you to have a cluster with usless data.
This is a WARNING article, and it comes out after I have being working on define internal blueprint on how to perform DDL operation using RSU safely.
The fun, if fun we want to call it, comes as usual by the fact that I am a curious guy and I often do things my way and not always following the official instructions.
Anyhow, lets us go straight to the point and describe what can happen on ANY MySQL/Galera installation.
The environment
The test environment, MySQL/Galera (Percona PXC 5.6.20 version).
The cluster was based on three nodes local no geographic distribution, no other replication in place then Galera.
Haproxy on one application node, simple application writing in this table:
Table: tbtest1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
… |
Creating a simple Load Balance client for a MySQL
Cluster
There are few key points in using the Connector/J with Load
Balancing on MySQL Cluster
- Dynamic JMX with Connector/J
- Timeout value in the blacklist with Connector/J
The following code piece is used on my notebook with MySQL
Cluster running on 2 x VMs. IPs for accessing the 2 MySQL
Nodes on the Cluster are 192.168.56.104 and 192.168.56.105.
The port number with the 2 x MySQL Nodes are the same with
the value of "3306".
Here is the MySQL Cluster status with MySQL Cluster Manager
(MCM)
…
I'm happy to announce the release of mylvmbackup version 0.16. The source package is now available for download from http://lenzg.net/mylvmbackup/ and https://launchpad.net/mylvmbackup.
Installation packages for a number of platforms can be obtained from the openSUSE Build Service.
Version 0.16 adds support for sending out SNMP traps in case of backup successes or failures. I'd like to thank Alexandre Anriot for contributing this new feature and his patience with me.
Please see the ChangeLog and bzr …
[Read more]Introduction
With the introduction of Galera replication for MySQL, Codership has, in my opinion, provide the most significant support to MySQL that the community had seen in the last tree years.
Codership had filled a significant gap in MySQL replication capability, succeeding in a task where many before had failed.
Not only Codership is constantly committed in doing their solution better and more solid, and they are the most friendly and helpful team I have met in years.
In short chapeau to all of the guys! Great job, I am really proud to have the opportunity to discuss, interact with you.
Said that, no product or code around is unmingled of errors and/or issues at different level. So also if Galera help us a lot solving many replication and architectural issues it still has some limitation that must be taken in consideration.
Galera is easy to setup, especially to perform a basic setup, which …
[Read more]Jeremy Cole has an excellent article on why a mysqld instance will swap despite proper memory settings on modern hardware here. A quick hand-wave of a summary goes: in modern architecture, every process is, by default, limited to a 1/Nth of the available memory on a machine, where N is the number of cores, and will start to swap on disk when all the available memory in that 1/Nth is consumed.
The eventual solution for a large, single-instance mysqld-running machine is to enable numa_interleave in the mysqld_safe section of the config:
Implicitly, when that flag is set, mysqld is being started by mysqld_safe with a numactl flag that will spread the memory …
[Read more]You might have encountered situations where you had to kill some specific select queries that were running for long periods and choking the database. This post will go into more detail with an example of report query offloading.
Report query (select) offloading to a slave server is a common practice to reduce the workload of the master DB server. The long running selects will be executed in the slave for report generation. I have observed in many cases where the slave used to get delayed or the slave DB encounters a slowdown due to some heavy long-running orphaned selects from some wrong reports.
There are two main ways to kill queries in MySQL: 1. use custom scripts that match on a regular expression, or 2. use a tool written and supported by Percona that is designed to kill queries based on matching conditions. Below is one script that will help you to kill those queries. The script will take the process list from MySQL and …
[Read more]Hi Apache Friends!
We just released new versions of XAMPP for all platforms with latest PHP versions: 5.5.19 and 5.6.3. We simplified the versioning for XAMPP releases and we now base the version number on the bundled PHP version, so you can more easily tell what is in the stack.
In addition to the component upgrades below, we also included a new beta Welcome page, which includes new tutorials. We will continue to add more and would love to get your feedback!
The following guides are available for Windows and Linux in the current versions:
