I checked in some improvements to Shard-Query.

Now STD, STD_SAMP, VAR and VAR_SAMP can be orders of magnitude faster for large data sets. This is because they are now distributed like COUNT, AVG and other fully distributable MySQL aggregate functions.   Prior to this change, my test query would create a 22GB (530M row) temporary table.  It now creates a one row temporary table.  This reduces network traffic, temporary storage space and increases performance.

Shard-Query better reports initialization errors. This mostly means that if you don’t have gearmand running you will no longer get a cryptic PHP output, but a nice error message.

You can change the storage engine for the repo by changing only one line in shard_query.sql. This lets you more easily install on Infobright, which needs MyISAM tables, not InnoDB tables in the repo.

On the road again - FOSSAsia

It has been a few busy months until now. I have moved from Italy to Thailand, and the move has been my first priority, keeping me from attending FOSDEM and interacting with social media. Now I start catching my breath, and looking around for new events to attend. But before I get into this, let’s make a few things clear:

• I am still working for Continuent. Actually, it’s because of my company flexibility that I could move to a different country (a different continent, 6 time zones away) without much trouble. Thanks, Continuent! (BTW: Continuent is hiring! )
• I am still involved with MySQL activities, events, and community matters. I just happen to be in a different time zone, where direct talk with people in Europe and …

As usual, you can find the slides from PLUK 2013 and FOSDEM 2014 on [Plus].
You have just to access to the slides page and free up some time to discover and read all the referenced content.

Remember the programs of these fantastic events :

• PLUK 2013 : https://www.percona.com/live/london-2013/program/schedule/sessions
• FOSDEM 2014 : https://fosdem.org/2014/schedule/track/mysql/

Now, I’ve just discovered that many slides are missing for PLUK 2013 on the perconalive website.

For latecomers, it’s still time to upload your slides from your dedicated speaker page.
Please, do it quickly, the …

One of the most expensive database operations is performing Data Definition Language (DDL, e.g. CREATE, DROP, ALTER, etc.) statements, specially, the ALTER statements because MySQL blocks the entire table for both reads and writes while modifying the table.

For the huge tables, this might take hours to get the table changed which affects the application, so that, a good planning is required for such operations in order to avoid doing these changes during the peak times. For those people who have 24/7 services or limited maintenance window, DDL on huge tables is a really nightmare.

Percona developed a very good tool called pt-online-schema-change (version 2.2.6 at the time of writing this article) to perform such operations online without blocking/affecting …

One of the most expensive database operations is performing Data Definition Language (DDL, e.g. CREATE, DROP, ALTER, etc.) statements, specially, the ALTER statements because MySQL blocks the entire table for both reads and writes while modifying the table.

For the huge tables, this might take hours to get the table changed which affects the application, so that, a good planning is required for such operations in order to avoid doing these changes during the peak times. For those people who have 24/7 services or limited maintenance window, DDL on huge tables is a really nightmare.

Percona developed a very good tool called pt-online-schema-change (version 2.2.6 at the time of writing this article) to perform such operations online without blocking/affecting …

Last week I needed to fast-forward a delayed MySQL replica in order to recover some data. I use pt-slave-delay to keep this replica X days behind the master, and I needed to fast-forward it to be about X-2 days behind the master instead.

I wanted to catch the replica up to a precise moment in time, and it was important that it not go past that point until I was done recovering the data I needed.

I knew there was a command to do this, but I couldn't remember the syntax. Since I figured pt-slave-delay was implemented using this command, I just opened the perl script and searched around until I found the syntax I was looking for. Here it is:

``` START SLAVE [SQL_THREAD] UNTIL

MASTER_LOG_FILE = 'log_name', …

This week, we talk about the new and innovative talks appearing at Percona Live. Ear Candy is about warming up the innodb buffer pool cache, and At the Movies talks about zero-cost joins.

Pecona Live
Percona Live 2014 is Tuesady April 1st through Friday April 5th at the Santa Clara Convention Center in Santa Clara, California.

Percona Live 2014 conference site

Register for Percona Live - save $100 if you register on or before March 2nd!

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Moving data between databases is hard. Without ever intending it, I seem to have spent a lifetime working on solutions for getting data into and out of databases, but more frequently between. In fact, my first job out of university was migrating data from BRS/Text, a free-text database (probably what we would call a NoSQL) into a more structured Oracle.

Today I spend some of my time working in Big Data, more often than not, migrating information from existing data stores into Big Data so that they can be analysed, something I covered in more detail here:

http://www.ibm.com/developerworks/library/bd-sqltohadoop1/index.html
http://www.ibm.com/developerworks/library/bd-sqltohadoop2/index.html
…

The MySQL February Newsletter is available! Find out the latest news on MySQL products and MySQL Connect 2014, and read the technical tips written by MySQL experts at Oracle and in the community. Below are the highlights in this edition:

• Start Preparing for MySQL Connect 2014 Call for Papers
• New GA Release: MySQL for Visual Studio
• Blog: State of the UNION
• Blog: New MySQL Web Installer -- Have You Tried It Yet?
• Blog: MySQL Workbench: Frequent Crashes on Mac OS X? This Might Be The Fix
• Event: MySQL Seminars Are Coming to a City Near You

You can read it online or subscribe to it to receive the latest updates right in your inbox. Watch this …

MariaDB 10.0.8 was recently released as RC ("Release Candidate"), and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.8/

This is the first RC release of MariaDB 10.0. It is primarily a bug-fix and polishing release, and all features planned for MariaDB 10.0 GA are included in this release.

There were 6 notable changes in MariaDB 10.0.8:

1. InnoDB upgraded to version 5.6.14

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