One of the most popular plugin types both in MariaDB and MySQL is INFORMATION_SCHEMA plugin type. INFORMATION_SCHEMA plugins add new tables to the INFORMATION_SCHEMA. There are lots of INFORMATION_SCHEMA plugins, because they can be used to show just anything to the user and are very easy to write.

MariaDB 10.1.1 comes with nine INFORMATION_SCHEMA plugin:

• Feedback — shows the anonymised server usage information and can optionally send it to the configured url.
• Locales — lists compiled-in server locales, implemented by Roberto Spadim
• METADATA_LOCK_INFO — Lists metadata locks in the server. Implemented by Kentoku Shiba
• …

Every now and then there is a need to execute certain SQL statements conditionally. Easy, if you do it from your PHP (or Java or whatever) application. But if all you have is pure SQL? There are two techniques that MariaDB and MySQL use in the mysql_fix_privilege_tables.sql script (applied by mysql_upgrade tool).

1. Create a stored procedure with IF statements inside, call it once and drop it. This requires the user to have the CREATE ROUTINE privilege and mysql.proc table must exist and be usable (which is not necessarily true — we’re doing it from mysql_upgrade, right?).
2. Use dynamic SQL, like
   

   SET @str = IF (@have_csv = 'YES',
                  'CREATE TABLE IF NOT EXISTS general_log (
                     event_time TIMESTAMP(6) NOT NULL,
                     user_host MEDIUMTEXT NOT NULL,
                     thread_id BIGINT(21) UNSIGNED NOT NULL, …

Yes! In MariaDB 10.1.1 tables in PERFORMANCE_SCHEMA do not use .frm files. These files are not created, not read — in fact, PERFORMANCE_SCHEMA tables never touch the disk at all.

This became possible due to a lesser-known feature of MariaDB — new table discovery (“old table discovery” was implemented in MySQL for NDB Cluster in 2004), implemented in MariaDB 10.0.2. Instead of reading and parsing .frm files, MariaDB simply asks PERFORMANCE_SCHEMA table, what structure it has, and because these tables always have a fixed structure, the table directly returns it to MariaDB with no need for any external data dictionary.

It also means, you never need to upgrade PERFORMANCE_SCHEMA tables, they always have the correct structure corresponding to the MariaDB version …

As you all know MariaDB supported roles since the MariaDB release 10.0.5. They were implemented almost exactly as specified in the SQL Standard 2003, features T331 “Basic roles” and T332 “Extended Roles”.

But we were often hearing complains, users were not satisfied with purely standard set of features. In particular, the standard specified that one had to do

SET ROLE foobar;

to be able to use privileges, granted to the role foobar. This was not always convenient and sometimes not even possible (imagine, you need to grant role privileges to an account used by a closed-source application). There had to be some way to enable a given role automatically, when a user connects.

To solve this issue we have introduced the concept of a default role. A default role for given user is automatically enabled when this user …

Introduction

This blog is a follow up to my original blog in https://blog.mariadb.org/performance-evaluation-of-mariadb-10-1-and-mysql-5-7-4-labs-tplc/ . First of all I would like to thank for all the comments I received. Based on the comments there was a concern if the differences seen on performance was due to different configuration setup. Furthermore, I did not know that there was a configuration variable to get similar multi-threaded flush mechanism on MySQL as there is on MariaDB. To find out if the different configuration variables or different defaults were the reason for different performance, I ran several rounds of new tests.

Test 1

Changing number of buffer pool instances or value of innodb thread concurrency do not seem to have significant effect on at least LinkBench benchmark …

This post walks through some examples of using the geospatial functions provided by MySQL and Sphinx. Enjoy! Getting Started First of all, here are some helpful resources: We wrote about geospatial search with Sphinx in this blog post. It has a more Sphinx-specific focus than this post. Alexander Rubin wrote these helpful articles: “Creating Geo [...]

Download MariaDB Galera Cluster 10.0.13

Release Notes Changelog What is MariaDB Galera Cluster?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 10.0.13. This is a Stable (GA) release.

See the …

You probably already know that Sphinx supports MySQL binary network protocol. But, if you haven’t heard– Sphinx can be accessed with the regular ol’ MySQL API. Pretty much any language you use to query MySQL can be used to query Sphinx. So, in this post, to demonstrate how using ‘SphinxQL’ (our subset of SQL) makes [...]

Introduction

Evaluating the performance of database systems is a very demanding task. There are a lot of hard choices to be made, e.g.:

• What operating system and operating system version is to be used
• What configuration setup is to be used
• What benchmarks are to be used and how long are the warm-up and measure times
• What test setups are to be used
• What version of the database management system is used
• What storage engine is used

While performance evaluation is mostly machine time, there is still a lot of hard work for the human monitoring the tests. In this blog post we have made following choices:

• We’re using an Intel Xeon E5-2690 @ 2.9GHz CPU containing 32-cores and Linux 3.4.12 with 132G main memory. The database is stored on a Fusion-IO ioDrive2 Duo 2.41TB Firmware v7.2.5, rev 110646, using Driver 3.3.4 build 5833069. The …

There may come a time when you want to collect some of your emails, put them into a database, and search them with Sphinx. If that time has come, you may enjoy this blog post. It will outline one way to get emails from Gmail into MySQL (with PHP’s IMAP extension) so that they become [...]