July 31, 2014

Using the new spatial functions in MySQL 5.6 for geo-enabled applications

Geo-enabled (or location enabled) applications are very common nowadays and many of them use MySQL. The common tasks for such applications are: Find all points of interests (i.e. coffee shops) around (i.e. a 10 mile radius) the given location (latitude and longitude). For example we want to show this to a user of the mobile […]

Replication of the NOW() function (also, time travel)

Notice the result of the NOW() function in the following query. The query was run on a real database server and I didn’t change the clock of the server or change anything in the database configuration settings.

You may proceed to party like it is 1999. How can the NOW() function return a value […]

Statement based replication with Stored Functions, Triggers and Events

Statement based replication writes the queries that modify data in the Binary Log to replicate them on the slave or to use it as a PITR recovery. Here we will see what is the behavior of the MySQL when it needs to log “not usual” queries like Events, Functions, Stored Procedures, Local Variables, etc. We’ll […]

Stored Function to generate Sequences

Today a customer asked me to help them to convert their sequence generation process to the stored procedure and even though I have already seen it somewhere I did not find it with two minutes of googling so I wrote a simple one myself and posting it here for public benefit or my later use

Memory allocation in Stored Function

UPDATE : Post is not actual anymore Not so long time ago I had task to update string column in table with 10mil+ rows, and, as the manipulation was non-trivial, I decided this task is good to try Stored Function. Function written – go ahead. Since 5 min I got totally frozen box with no […]

Paul McCullagh answers your questions about PBXT

Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul! What’s the “ideal” use case for the PBXT engine, and how does it compare in performance?  When would I […]

GROUP_CONCAT useful GROUP BY extension

(There is an updated version of this post here) MySQL has useful extention to the GROUP BY operation: function GROUP_CONCAT: GROUP_CONCAT(expr) – This function returns a string result with the concatenated non-NULL values from a group. Where it can be useful?

Simple MySQL Master HA with mysqlnd_ms

I had the pleasure of presenting to the PHP Users Group Philippines a few days ago about mysqlnd_ms. The mysqlnd plugin, MySQL Master Slave, is a transparent layer on top of mysqlnd extension. This allows you to do read-write splitting and slave reads load balancing without needing to change anything from your application. But do […]

Using UDFs for geo-distance search in MySQL

In my previous post about geo-spatial search in MySQL I described (along with other things) how to use geo-distance functions. In this post I will describe the geo-spatial distance functions in more details. If you need to calculate an exact distance between 2 points on Earth in MySQL (very common for geo-enabled applications) you have at […]

InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables without primary keys This scalability issue is caused by the usage of tables without primary keys. This issue typically shows […]