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 …

A very old post of mine in 2009, MySQL’s stored procedure language could be so much more Useful suggested that it would be nice if MySQL could be adapted to use compound statements directly from the command line in a similar way to the language used for stored procedures. I’ve just seen that this seems to … Continue reading MariaDB 10.1 Brings Compound Statements

October 17, 2014 By Severalnines

Integrating ClusterControl with a corporate LDAP directory is a common task for many IT organizations. In an earlier blog, we showed you how to integrate ClusterControl with OpenLDAP. In this post, we will show you how to integrate with FreeIPA and Windows Active Directory. 

How ClusterControl Performs LDAP Authentication

ClusterControl supports up to LDAPv3 protocol based on RFC2307. More details on this in the documentation.

When authenticating, ClusterControl will first bind to the directory tree server (LDAP …

I still get asked about the lost+found directory enough, and so I wanted to provide a current update.

The lost+found directory is a filesystem directory created at the root level of a mapped drive. Thus this is common to see if you create your mysql datadir at the root level of a mapped drive.

In the past, you could ignore it, if it wasn’t too problematic for you, or you could move your datadir down a level, and then it wouldn’t be created in the datadir anymore.

However, there is now the –ignore-db-dir option. It is actually not too new (it’s been in MariaDB since 5.3.9 and 5.5.28, and in MySQL as of 5.6.3), but I don’t think many are too familiar with it.

But when you do run into this problem, some/many would prefer to add a single line to the config file rather than move the datadir.

To do this, just add the following option to your my.cnf file, under the [mysqld] section (it cannot be set …

For some reason, we’ve been getting a lot of issues with ORDER BY optimization recently. The fixes have passed Elena Stepanova’s scrutiny and I’ve pushed them to MariaDB 10.1. Now, MariaDB’s ORDER BY ... LIMIT optimizer:

• Doesn’t make stupid choices when several multi-part keys and potential range accesses are present (MDEV-6402)
• Always uses “range” and (not full “index” scan) when it switches to an index to satisfy ORDER BY … LIMIT (MDEV-6657)
• Tries hard to be smart and use cost/number of records estimates from other parts of the optimizer (MDEV-6384, MDEV-465, MySQL …

MariaDB 5.5.40 was recently released (it is the latest MariaDB 5.5), and is available for download here:

https://downloads.mariadb.org/mariadb/5.5.40/

This is a maintenance release, and so there are not too many big changes of note, just a number of normal bug fixes. However, there are a few items worth mentioning:

• Includes all bugfixes and updates from MySQL 5.5.40 (MySQL 5.5.40 Overview and Highlights)
• XtraDB updated to the version from …

MariaDB 5.5 and then MySQL 5.6 got Index Condition Pushdown (ICP) optimization (initially coded by yours truly). The idea of ICP is simple: after reading the index record, check the part of WHERE condition that can be computed using index columns, and only then read the table record. That way, we avoid reading table rows that don’t satisfy index condition:

It seems apparent that ICP can never make things slower. The WHERE clause has to be checked anyway, and not reading certain records can only make things faster.

That was what I thought, too, until recently Joffrey Michaie observed the contrary “in the wild”: we’ve got a real-world case where using Index Condition Pushdown was slower than not using it: …

October 9, 2014 By Severalnines

Installing, configuring, deploying databases and performing repetitive administrative tasks are all part of a DBA’s or sysadmin’s job. This can get pretty repetitive and overwhelming if you are part of a centralized IT team, running multiple databases for your organization’s different departments, or a managed hosting provider responsible for setting up and operating databases for external clients. One way to get out of this ‘manual, repetitive task’ business is through a Database as a Service (DBaaS).

DBaaS is a way of delivering database functionality as a service to one or more consumers. A DBaaS platform would provide automated procedures for database deployment, monitoring, backups, recovery/repair, scaling, security/multi-tenancy, etc. This type of automation is especially useful where agility is needed, e.g. for systems that require elasticity by scaling out or scaling back at short …

Good news for those wanting to run MariaDB on POWER systems, the latest 10.0 bzr tree (as of a couple of weeks ago) builds and runs well!

I recently pulled the latest MariaDB 10.0 from BZR and built it on a POWER8 system in the lab to run some quick tests. The MariaDB team has done some work on getting MariaDB to run on POWER recently, a bunch of which is based off my work on MySQL on POWER.

There’s obviously still some work in progress going on, but my initial results show performance within around 10% of MySQL, so with a bit of work we will hopefully see MariaDB reach performance parity.

One interesting find was the code to account for thread memory usage uses a single atomic variable: this does not scale and does end up showing up on profiles.

I’ll comment more on the code in a future post, but it looks like we will have MariaDB being functional on POWER in an upcoming release.

MariaDB 10.0.14 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.14/

This is the fifth GA release of MariaDB 10.0, and 15th overall release of MariaDB 10.0.

This is primarily a bug-fix release. (MariaDB 10.0 is the current stable series of MariaDB. It is an evolution of the MariaDB 5.5 with several entirely new features not found anywhere else and with backported and reimplemented features from MySQL 5.6.)

Here are the main items of note:

1. TokuDB upgraded to 7.5.0
2. XtraDB upgraded to 5.6.20-68.0
3. InnoDB upgraded to 5.6.20
4. …