Percona Server 5.6.21+ and MySQL 5.7.8+ offer the super_read_only option that was first implemented in WebscaleSQL. Unlike read_only, this option prevents all users from running writes (even those with the SUPER privilege). Sure enough, this is a great feature, but what’s the relation with GTID? Read on!

TL;DR

Enabling super_read_only on all slaves when using GTID replication makes your topology far less sensitive to errant transactions. Failover is then easier and safer because creating errant transactions is much harder.

GTID replication is awesome…

For years, all MySQL DBAs in the world have been fighting with positioning when working with replication. Each time you move a slave from one master to another, you must be very careful to start …

The MySQL Fabric team is pleased to announce that a new (GA) release is now available. This release includes several improvements in terms of stability and usability (bug fixes and feature enhancements). In a nutshell:

• Two new types of users for backup and restore are now available allowing a better managements of the required privileges for each user type.

…

The MySQL Fabric team is pleased to announce that a new (GA) release is now available. This release includes several improvements in terms of stability and usability (bug fixes and feature enhancements). In a nutshell:

• Two new types of users for backup and restore are now available allowing a better managements of the required privileges for each user type. More information: http://dev.mysql.com/doc/mysql-utilities/1.5/en/fabric-create-user.html 
• An example script for pacemaker was added to the source packages to help provide an HA solution using a single Fabric node. More information: http://dev.mysql.com/doc/mysql-utilities/1.5/en/fabric-pacemaker.html
• The Connector/Python minimum …

In Python it is easily possible to findout the name of a Unicode character and findout some properties about that character. The module which does that is called unicodedata.

An example:

>>> import unicodedata
>>> unicodedata.name('☺')
'WHITE SMILING FACE'

This module uses the data as released in the UnicodeData.txt file from the unicode.org website.

So if UnicodeData.txt is a 'database', then we should be able to import it into MySQL and use it!

I wrote a small Python script to automate this. The basic steps are:

• Download UnicodeData.txt
• Create a unicodedata.ucd table
• Use LOAD DATA LOCAL INFILE to load the data

This isn't difficult especially because the file doesn't have the actual characters in it. It is …

Recently, we had an issue in our application which is a single page application(SPA). We have all the functionality in a single page and most of the data and view changes happen through ajax requests and iframe page displays.We are using CodeIgniter framework for this application. So sometimes what happened was the user was logged out while accessing the application and this occurred once a while for 1 or 2 users, not a reproducible case one would say.Before starting on the case, I would like to specify the steps which CodeIgniter takes for checking session for any request.Steps:
1. Read session cookie sent from browser.
2. Read session cookie process proceeds with below step checks (If any one step fails below, it results in create one session cookie)
2a. Checks if session cookie is present
2b. Checks if it is a valid session cookie by using it's decryption algorithm check
2c. If  valid session, then check if …

It's migration time. There was another project that I use often and was still in Launchpad. The Sample Employees Database is now on GitHub, under the same license it had before (CC A-SA 3).

Figure 1 - Employees database
This database is interesting because it is not too small (like Sakila) and not too big. It has enough data to allow you to test in a non trivial way.
Installation and testInstalling the database is easy:

$ git clone https://github.com/datacharmer/test_db.git
$ cd test_db
$ mysql < employees.sql
INFO
CREATING DATABASE STRUCTURE
INFO
storage engine: InnoDB
INFO
LOADING departments
INFO
LOADING employees
INFO
LOADING dept_emp
INFO
LOADING dept_manager
INFO
LOADING titles
INFO …

Benchmark for NVMFS (supports atomic writes ,so we can close double-write option on specific MySQL version )

tips: some Flash-based cards could support large block map , the main idea is to avoid fractured page writes.

http://www.vmcd.org/docs/nvmfs_benchmark.pdf

Percona’s CTO Vadim Tkachenko wrote a response to my Galera Snapshot Isolation post last week. I think Tkachenko may have misunderstood some of my results, and I’d like to clear those up now. I’ve ported the MariaDB tests to Percona XtraDB Cluster, and would like to confirm that using exclusive write locks on all reads, as Tkachenko recommends, can recover serializable histories. Finally, we’ll address Percona’s documentation.

I didn’t use the default isolation levels

But there I need to add quite IMPORTANT addition: it may leave data in inconsistent state if you use SPECIAL TYPE of transactions in default isolation levels that Aphyr uses in his test.

My tests did not use the default isolation …

Percona’s CTO Vadim Tkachenko wrote a response to my Galera Snapshot Isolation post last week. I think Tkachenko may have misunderstood some of my results, and I’d like to clear those up now. I’ve ported the MariaDB tests to Percona XtraDB Cluster, and would like to confirm that using exclusive write locks on all reads, as Tkachenko recommends, can recover serializable histories. Finally, we’ll address Percona’s documentation.

I didn’t use the default isolation levels

But there I need to add quite IMPORTANT addition: it may leave data in inconsistent state if you use SPECIAL TYPE of transactions in default isolation levels that Aphyr uses in his test.

My tests did not use the default isolation …

Percona’s CTO Vadim Tkachenko wrote a response to my Galera Snapshot Isolation post last week. I think Tkachenko may have misunderstood some of my results, and I’d like to clear those up now. I’ve ported the MariaDB tests to Percona XtraDB Cluster, and would like to confirm that using exclusive write locks on all reads, as Tkachenko recommends, can recover serializable histories. Finally, we’ll address Percona’s documentation.

I didn’t use the default isolation levels

But there I need to add quite IMPORTANT addition: it may leave data in inconsistent state if you use SPECIAL TYPE of transactions in default isolation levels that Aphyr uses in his test.

My tests did not use the default isolation …