If you use a storage engine that supports transactions, you probably have faced or heard of deadlock's.

From MySQL Documentation:
“Always be prepared to re-issue a transaction if it fails due to deadlock. Deadlocks are not dangerous. Just try again.”

At work, we had an important job that sometimes were failing due to dead lock. I wanted to enhance it, so it will do what the documentation says ( Retry the transaction ). In order to do that, I wanted to have a scenario where I was able to reproduce the deadlock and the victim transaction was the one from the job I was fixing.

Create a deadlock is simple, you just need to have 2 sessions that each one holds a lock that the other is waiting for. For example:
We have a table that has 4 entries on it (entry 1, entry 2, entry 3, entry 4) and we have 2 …

I'm known for telling "Don't use references" (also as video) as those cause different problems (i.e. with foreach) and hurt performance. The reason for the performance loss is that references disable copy-on-write while most places in PHP assume copy-on-write. Meanwhile we have PHP 7. In PHP 7 the internal variable handling changed a lot among other things the reference counting moved from the zval, the container representing a variable, to the actual element. So I decided to run a little test to verify my performance assumption was still valid.

In my test code I'm calling a function which calls strlen (one of the cheapest functions in PHP - PHP strings …

This blog post was co-authored by Peter Sylvester and Valerie Parham-Thompson

Introduced in version 10.1.3 (and with substantial changes in 10.1.4), the MariaDB data encryption at rest feature allows for transparent encryption at the tablespace level for various storage engines, including InnoDB and Aria.

Before now, there have been only two widely accepted encryption methods for MySQL/MariaDB: encryption at the file system level, or encryption at the column level. For comparison, we’ll do a brief overview of how these work, as well as the pros and cons typically associated with each option.

File System Encryption

This is performed by setting a file system to be encrypted at the block level within the operating system itself, and then specifying that the encrypted volume should be the location of the data directory for MySQL/MariaDB. You can also use encrypted volumes to store MariaDB binary logs. …

This Log Buffer browses through Oracle, SQL Server and MySQL spaces and brings forth some of the useful blog posts for this week.

Oracle:

Conner throws it out of the park. As we all (hopefully) know, we should always deploy named program units (procedures/functions) within packages. Its a great method of encapsulation of logic.

Pythian’s Gleb talks about Azure on RAC. Microsoft Azure provides an acceptable and affordable platform for a training environment.

There are some performance improvements that require physical storage options to be set on tables or indexes. One particular technique that I will take as an …

Welcome to today’s installment of Planets9s, our weekly communication on all the latest resources and technologies we create around automation and management of open source databases. I trust that these resources will be useful to you and would love to get your feedback on them.

Download ClusterControl - The Full Monty Release for MySQL, MongoDB & PostgreSQL

This week we’re pleased to announce the release of ClusterControl 1.2.12. This release contains key new features, such as support for the latest versions of MySQL, MongoDB & PostgreSQL, operational reports and enhanced backup options, along with performance improvements and bug fixes. Worth highlighting are also the new replication features for Master & Slave, as well as SSL encryption of Galera

Replication links. …

Graph databases are great. But if I read more FUD about RDBMSs, I’m going to have another flashback to the 80’s where someone is telling me about how you don’t want to dismantle your car every time you park it in the garage (OODBMS reference for the oldies).
I recently read a graph-database book that explained that every SQL join requires computing a cartesian product. And yesterday, a post that explained that equijoins have an exponential order of complexity. (I guess… if the exponent is 1.) It’s getting very frustrating to read through the inaccuracies and FUD, and now, to me, it is all just turning into

Which is why it was nice to see @guyharrison‘s even-handed and accurate treatment in his new book …

With our new ClusterControl 1.2.12 release we have added many new features like operational reports, enhanced backup options, SSL Encryption for Galera replication links and improved the support for external tools. One of these tools is CCBot, the ClusterControl chatbot.

CCBot is based on the popular Hubot framework originally created by Github. Github uses Hubot as their DevOps tools of choice and allowing them to do Continuous Integration and Continuous Delivery on their entire infrastructure. So what does Hubot allow you to do?

Hubot

Hubot is a chatbot that has been modelled after Github’s internal bot called hubot. The Hubot framework allows you to quickly create your own bot and extend it with various pre made scripts and …

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