(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?
Article about database design problems is being discussed by Kristian. Both article itself and responce cause mixed feellings so I decided it is worth commenting: 1. Using mysql_* functions directly This is probably bad but I do not like solutions proposed by original article ether. PEAR is slow as well as other complex conectors. I […]
Percona offers consulting (and training, and support, and development) services for MySQL and LAMP applications. We can help with all areas of the MySQL Server – Operations, Application Design, Custom Feature development, and so on. Please visit our company website to learn more about our MySQL consulting and other services for MySQL, our more than […]
Galera replication for MySQL brings not only the new, great features to our ecosystem, but also introduces completely new maintenance techniques. Are you concerned about adding such new complexity to your MySQL environment? Perhaps that concern is unnecessarily. I am going to present here some simple tips that hopefully will let fresh Galera users prevent […]
If you’ve been following this blog (my colleague, David Busby, posted about it yesterday) or any tech news outlet in the past few days, you’ve probably seen some mention of the “Heartbleed” vulnerability in certain versions of the OpenSSL library. So what is ‘Heartbleed’, really? In short, Heartbleed is an information-leak issue. An attacker can […]
The heartbleed bug was introduced in OpenSSL 1.0.1 and is present in 1.0.1 1.0.1a 1.0.1b 1.0.1c 1.0.1d 1.0.1e 1.0.1f The bug is not present in 1.0.1g, nor is it present in the 1.0.0 branch nor the 0.9.8 branch of OpenSSL some sources report 1.0.2-beta is also affected by this bug at the time of writing, […]
Today I gave a presentation on “Read/Write Splitting with PHP” for Percona Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as I could during the session, but here are […]
This is to follow up my previous post with kernel_mutex problem. First, I may have an explanation why the performance degrades to significantly and why innodb_sync_spin_loops may fix it. Second, if that is correct ( or not, but we can try anyway), than playing with innodb_thread_concurrency also may help. So I ran some benchmarks with […]
The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.
On March 29th, Iâ€™ll be giving a webinar whose title is â€œUnderstanding HandlerSocket – A NoSQL PlugIn For MySQLâ€. This is a continuation and extension of the talk I gave during the Percona Live Event in San Francisco back in February. We’ll ask, and answer, the following questions: What is HandlerSocket? Where does HandlerSocket fit […]