MariaDB 10.1.1: FLUSH and SHOW for plugins

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.

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MariaDB 10.1.1: Compound statements

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,
    server_id INTEGER UNSIGNED NOT NULL,
    command_type VARCHAR(64) NOT NULL,
    argument MEDIUMTEXT NOT NULL
    ) engine=CSV CHARACTER SET utf8 comment=”General log”‘,
    ‘SET @dummy = 0’);

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MariaDB 10.1.1: no more .frm’s for performance_schema tables

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. Read more

MariaDB 10.1.1: default roles

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). Read more

Three new MariaDB Releases

The MariaDB project is pleased to announce the immediate availability of the following:



MariaDB 10.1.1 is an Alpha release.

Download MariaDB 10.1.1

Release Notes Changelog What is MariaDB 10.1?

MariaDB APT and YUM Repository Configuration Generator

Don’t use alpha releases on production systems!

See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 10.1? Read more

MariaDB 5.5.40 now available

Download MariaDB 5.5.40

Release Notes Changelog What is MariaDB 5.5?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB 5.5.40. This is a Stable (GA) release.

See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 5.5? page in the MariaDB Knowledge Base for general information about the MariaDB 5.5 series.

Thanks, and enjoy MariaDB! Read more

MariaDB 10.0.14 now available

Download MariaDB 10.0.14

Release Notes Changelog What is MariaDB 10.0?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB 10.0.14. This is a Stable (GA) release.

See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 10.0? page in the MariaDB Knowledge Base for general information about the MariaDB 10.0 series.

Thanks, and enjoy MariaDB! Read more

Update on Performance measurement on MariaDB 10.1 and MySQL 5.7.4-labs-tplc

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. Read more