MySQL uses a cost-based optimizer to determine the best way to execute a query. It usually does a great job, but not all the time. There are different reasons for that. In some cases, it might not have enough information about the data and plan queries in a non-optimal way.  

The optimizer makes decisions based on statistics and some fixed costs per operation, but it does not understand the differences in hardware. For instance, disk access may have different costs depending on the type of storage used - SSD drives will have quicker access times than spindles, and can perform more operations in a given time. 

However, it is possible to impact how a query will be executed, and this is the topic of today’s blog. 

(Note that in MySQL 5.7, a lot of work has been done in order to improve this - users can modify the cost of different types of operations.)

This is the fourteenth installment in the …

Good news !

FOSDEM accepted our devroom for the next edition.

The MySQL devroom will take place on Saturday, January 30th 2016.

Stay tuned for the Call For Paper !!

Many years ago, I wrote about importing XML data into MySQL using ExtractValue(). The reason I'm revisiting the subject now is that I recently received an email request in relation to my old blog post:

I came across one of your blogs on importing XML data to MySQL using ExtractData() and I am trying to do the same using MySQL (5.5) database. However, I am new to this kind of method and would like to seek your expertise on this.

I have an XML file that looks like this:

<?xml version="1.0" encoding="UTF-8"?>
 <wovoml xmlns="http://www.wovodat.org"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 version="1.1.0" xsi:schemaLocation="http://www.wovodat.org phread2.xsd">
 <Data>
 <Seismic>
 <SingleStationEventDataset>
  <SingleStationEvent code="VTAG_20160405000000" owner1="169" …

A friend of mine asked me how they could automatically follow and unfollow people on Twitter. But they didn’t want to follow just anyone and everyone. He had a Twitter account which they used for recruiting in a very narrow construction industry. He wanted to find people in the same industry and follow them – hoping they would follow him back and learn about his open jobs. When I joined Twitter back in 2008, I wrote a similar program to automatically follow/unfollow users, but the Twitter API has changed quite a bit since then. So I decided to re-write the program with the latest Perl-Twitter API – Net::Twitter::Lite::WithAPIv1_1.

Before you attempt to use these scripts, you will need to register your application with twitter via apps.twitter.com, and obtain the following:

consumer_key
consumer_secret
access_token …

Information Age today unveiled the inaugural list of the UK’s top 50 data leaders and influencers

“Very strong on product and technical development of open-source databases, Vinay has helped global and UK businesses like BT, AutoTrader Group and Ping Identity to scale, manage and develop (data) cloud operations.” - as just announced by Information Age.

Congratulations to all the nominees and thanks to the selection committee at Information Age for this distinction!

Vinay is a passionate advocate of open source databases for mission-critical business. Prior to co-founding Severalnines, Vinay served as VP EMEA at Pentaho Corporation and held senior management roles at MySQL / Sun Microsystems / Oracle and Ericsson.

As our CEO, Vinay steers all …

We proudly announce General Availability (GA) of MySQL 5.7. Download now! MySQL 5.7.9 is an extremely exciting new version of the world’s most popular open source database that is 3x faster than MySQL 5.6, while also improving usability, manageability, and security. …

MariaDB TokuDB benchmark on FusionIO ,Compare TokuDB and InnoDB engines.

read: TokuDB_benchmark

Our friends at Datadog just published an insanely great three part series on monitoring Amazon RDS for MySQL using Datadog. You should go read that now.

Full disclosure, I helped review a couple of the drafts. (We don’t have any formal relationship, we’re just friends–although we do integrate VividCortex with Datadog for our customers).

My only suggestion for monitoring RDS+MySQL above and beyond what Datadog wrote is that query monitoring is vital. Your databases exist to run queries, so you really ought to monitor their performance! However that doesn’t really make sense for Datadog, since it isn’t a query centric monitoring platform. …

Many of you are coming to San Francisco next week for Oracle OpenWorld 2015 and many of you have already booked time on your calendars on Wednesday evening before the appreciation event. You are right — the Annual Oracle Bloggers Meetup, one of your favorite events of the OpenWorld, is happening at usual place and time!

What: Oracle Bloggers Meetup 2015.

When: Wed, 28-Oct-2015, 5:30pm.

Where: Main Dining Room, Jillian’s Billiards @ Metreon, 101 Fourth Street, San Francisco, CA 94103 ( …

MariaDB 10.1 shipped a few days ago, so it’s now a good time to focus on another important event. Last week we had a three day MariaDB developers meeting. It took place in Amsterdam (Oct 13-15). Meetings like this tend to have a great impact on the roadmap of the product. Booking.com was very kind […]

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