New version of JSON UDF functions has been just released. This is maintenance release which only contains fix for 4 bugs:

74090/19821398 `INSTALL_JSONUDFS` ISSUES A WARNING DUE TO TRUNCATION OF `VERSION_COMPILE_OS`
74091/19692634 `JSON_DEEP_MERGE`: DEEP CRASH IN `MERGE_TREE`
74092/19692628 CRASH WITH SECOND-HAND NULL IN PARAMETERS
74097/19693198 `CREATE_NEW_VALUE`: STACK BUFFER OVERFLOW, %LLD CAN'T FIT IN CHAR[20]

Also 0.3 branch becomes stable branch and no new features will be pushed to this branch in future. Previous stable branch (0.2) removed from MySQL Labs website.

…

Thu, 2015-01-15 16:18dipti_joshi_g

When I started my career in early nineties, the Internet, the open source software movement and the Linux operating system were in their infancy and MariaDB and MySQL did not exist. Today open source is a mainstream software delivery mechanism, and web applications are built upon open source stacks which include Linux and MariaDB. Sybase was the first relational database I worked with - a then leading relational technology in early nineties. Four months ago, I joined the team at MariaDB - a now leading open source relational database company where fast and cutting edge innovations take place.

Our team at MariaDB works with many organizations that use MariaDB to drive their web applications. Our business users tell us that, their success lies in their ability to deliver a quality customer experience, control cost, support a growing user base and stay competitive with faster innovation. In terms of …

In the MySQL Labs version of MySQL version 5.7, there is a new HTTP plugin. The HTTP plugin documentation from the labs site provides this information (from MySQL Labs):

The HTTP Plugin for MySQL adds HTTP(S) interfaces to MySQL. Clients can use the HTTP respectively HTTPS (SSL) protocol to query data stored in MySQL. The query language is SQL but other, simpler interfaces exist. All data is serialized as JSON. This version of MySQL Server HTTP Plugin is a Labs release, which means it’s at an early development stage. It contains several known bugs and limitation, and is meant primarily to give you a rough idea how this plugin will look some day. Likewise, the user API is anything but finalized. Be aware it will change in many respects.

In …

My dear colleagues,  Liz van Dijk, Dimitri Vanoverbeke, Kenny Gryp, also known as the “Party Team” are organizing the “Fosdem MySQL & Friends Devroom Community Dinner” !

Like last year, we’ll be renting a private space to allow for easy socializing. However, in light of this year’s 20th Anniversary of MySQL in May, as well as MariaDB’s 5th Anniversary in February, we want to take things to the next level, and give the night a true community feel. Our new location is available to us until 2AM, and is part of the ICAB buildings, closer to the ULB (more detailed directions on the eventbrite page).

As such, prepare for an evening of food prepared for the Community, by the Community. That’s right, your hosts will be firing up the pizza …

The other day a customer asked me to do capacity planning for their web server farm. I was looking at the CPU graph for one of the web servers that had Hyper-threading switched ON and thought to myself: “This must be quite a misleading graph – it shows 30% CPU usage. It can’t really be that this server can handle 3 times more work?”

Or can it?

I decided to do what we usually do in such case – I decided to test it and find out the truth. Turns out – there’s more to it than meets the eye.

How Intel Hyper-Threading works

Before we get to my benchmark results, let’s talk a little bit about hyper-threading. According to Intel, Intel® Hyper-Threading Technology (Intel® HT Technology) uses processor resources more …

In the MySQL Team, we are currently evaluating potential changes to the default server configuration for MySQL 5.7. For more context, please see my earlier post here.

One of the specific changes we would like to make is with the following three related replication and InnoDB settings:

Over the past few months I’ve written a couple of posts about dangerous debt of InnoDB Transactional History and about the fact MVCC can be the cause of severe MySQL performance issues. In this post I will cover a related topic – InnoDB Transaction Isolation Modes, their relationship with MVCC (multi-version concurrency control) and how they impact MySQL performance.

The MySQL Manual provides a decent description of transaction isolation modes supported by MySQL – I will not repeat it here but rather focus on performance implications.

SERIALIZABLE – This is the strongest …

The devroom’s schedule is now published on Fosdem’s website.

As you can see, it will be a heavy day full of good content. You can also notice that there won’t be any lunch-time break.

We advise you to then bring your lunch (like a sandwich) with you in the room and eat it between talks or prepare in advance when you will take your break during a talk you don’t want to attend (is it even possible ?).

This blog explains how relay log recovery happens in a scenario where an applier thread (SQL_Thread) is starting for the first time and its starting position is not available for relay log recovery operations. If you are using GTIDs with MASTER_AUTO_POSITION then the following is more or less irrelevant since we then employ a more resilient repositioning scheme. The potential issue described here will also not occur if you have employed crash-safe replication settings, including --sync_master_info=1. With those disclaimers out of the way, let’s proceed.

Background

A crash-safe slave in MySQL …

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