There’s no such thing as a schemaless database. I know, lots of people want a schemaless database, and lots of companies are promoting their products as schemaless DBMSs. And schemaless DBMSs exist. But schemaless databases are mythical beasts because there is always a schema somewhere. Usually in multiple places, which I will later claim is what causes grief.

There Is Always A Schema

We should define “schema” first. It comes from Greek roots, meaning “form, figure” according to my dictionary. Wikipedia says, roughly,

A database schema is its structure; a set of integrity constraints imposed on a database. These integrity constraints ensure compatibility between parts of the schema.

In other words, a schema expresses expectations about what fields exist in a database, and what their types will be. It also enforces those expectations, at least to some extent (there’s usually some …

Analyzing transactional data is becoming increasingly common, especially as the data sizes and complexity increase and transactional stores are no longer to keep pace with the ever-increasing storage. Although there are many techniques available for loading data, getting effective data in real-time into your data warehouse store is a more difficult problem.In this webinar-on-demand we showcase

In this post I will share a recovery scenario of a MySQL database restore from the binary logs. This post is also a good example of how we can achieve…

The post How to Restore / point in time recovery using binary logs MySQL first appeared on Change Is Inevitable.

If you’ve ever looked at the COM_XYZ status counters in MySQL’s SHOW STATUS output, you’ve probably seen Com_admin_commands. It’s not clear what this means, but it can be a major contributor to overall COM_ counters, and it’s actually quite important for server and application performance, as well as being a marker of code quality. In this blog post I’ll explain what the counter really means, and then as a bonus I’ll demonstrate that VividCortex will show you exactly what’s going on in the murkiness of “admin commands.”

What Does The Com_admin_commands Counter Mean?

The first question is “what is this counter?” The manual isn’t really helpful. It just says the following:

The Com_xxx statement counter variables …

Introduction

Causal consistency [1] is one of the consistency criteria that can be used on distributed databases as consistency criteria.

Distributed database provides causal consistency if read and write operations that are causally related are seen by every node of the distributed system in the same order. Concurrent writes may be seen in different order in diffrent nodes.  Causal consistency is waker than sequential consistency [2] but stronger than eventual consistency [3]. See earlier blog for more detailed description on eventual consistency https://blog.mariadb.org/eventually-consistent-databases-state-of-the-art/.

When a transaction performs a read operation followed later by a write operation, even on different object, the first read is said to be causally ordered before the write. This is because the …

Earlier this week, I presented a webinar on MySQL High Availability options for MySQL – what they are and how to choose the most appropriate one for your application.

The replay of this webinar can now be viewed here or if you just want to look at the charts then scroll down. At the end of this post, I include a summary of the Q&A from the webinar.

How important is your data? Can you afford to lose it? What about just some of it? What would be the impact if you couldn’t access it for a minute, an hour, a day or a week?

Different applications can have very different requirements for High Availability. Some need 100% …

MySQL 5.7 has had some great improvements within Performance Schema to be able to better trace what connections are doing, from adding memory information, through to transaction information, metadata locking, prepared statements, and even user variables, so far (there is still more to come in the next release – stay tuned).

Of course there are other improvements on top of this as well, such as the …

Thanks to everyone who attended and participated in last week’s webinar on ‘A DevOps Guide to Database Infrastructure Automation for eCommerce’. If you missed the sessions or would like to watch the webinar again & browse through the slides, they are now available online.

Our guest speaker this time was Riaan Nolan of Foodpanda/Rocket Internet. Topics included a roundup of infrastructure challenges faced by online retailers: multi-datacenter/cloud environments, configuration management, health and performance monitoring, capacity analysis and planning, elastic scaling, and automatic failure handling. Thanks again to Riaan for taking the time to speak to us!

The full agenda included: 

• eCommerce infrastructure challenges in 2014, including a sample workflow chart outlining: 
• Puppet, GitHub, Capistrano, Nginx, PHP5-FPM / Ruby, Percona XtraDB, Couchbase, SOLR, GlusterFS
…

I visited a customer some weeks back and saw some regression problem during an upgrade to MySQL 5.6. Problem was during initial setup of database, the CREATE TABLE statements was running much slower on MySQL 5.6 compared to MySQL 5.5.

I created a simple test case where I create one SQL file containing 1000 CREATE TABLE using the following statement syntax: CREATE TABLE TNNNN (i int, name VARCHAR(12))ENGINE=InnoDB;

Tested MySQL Versions:

• MySQL 5.5.42
• MySQL 5.6.22

OS: Ubuntu 14.04
HW: My Toshiba Portege laptop with 2 cores and SSD disk

MySQL 5.5.42 (Default settings)
Lets first get our baseline by running 10 runs: mysql test < /tmp/1000tables
Result: average execution time is 7.5 seconds

MySQL 5.6.22 (Default settings)
Lets first get our baseline by running 10 runs: mysql …

Coderhsip is pleased to announce a new release of Galera Cluster for MySQL consisting of MySQL-wsrep 5.6.21 and Galera 3.9, wsrep API version 25.

This release incorporates all changes up to MySQL 5.6.21 and numerous fixes  and enhancements specific to Galera replication.

Galera Cluster is now available as targeted packages and package repositories for a number of Linux distributions, including Ubuntu, Debian, Fedora, CentOS, OpenSUSE and SLES. Obtaining packages using a package repository removes the need to download individual files and facilitates the deployment and upgrade of Galera nodes.

This and future releases will be available from http://www.galeracluster.com, while previous releases remain available on LaunchPad. The source repositories and bug tracking are now on http://www.github.com/codership .

RELEASE NOTES

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