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“MariaDB Frequently Asked Questions in various MariaDB job interviews by interviewer. The set of questions are here to ensures that you offer a perfect answer posed to you. So get preparation for your new job interview”



55 MariaDB Questions And Answers

21⟩ How to move Process Names, Directories, Tcp Port Etc From Mysql To Mariadb?

It is important to keep same defaults as MySQL. At least for now. As stated right at the top of the introduction in About MariaDB, MariaDB is an enhanced, drop-in replacement for MySQL. This means that MariaDB is designed such that you can simply replace an installation of MySQL with an installation of MariaDB without having to change anything in your application setup or config files. MariaDB offers all of the features available inside MySQL and behaves exactly the same. Plus it offers a completely free implementation of some features only available in the commercial (paid) version of MySQL Enterprise.

The issue of conflicts (like using the same port) does not arise, since for most installations only one or the other will be installed: MySQL or MariaDB. That said, for testing, comparison, and development purposes there may be a need to run both, or even multiple versions of MariaDB on the same server and it is possible to install both MariaDB and MySQL, or two versions of MariaDB, in such a way that they both coexist side by side but it is not recommended for the majority of users.

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22⟩ Do you know who Is Behind Mariadb?

The MariaDB project is the brainchild of Michael "Monty" Widenius, the founder of MySQL®, Monty Program Ab (nowMariaDB Corporation), and a founding member of the MariaDB Foundation.

The core team consists of developers sponsored by the MariaDB Foundation, companies and individuals who are members of the Foundation, and people in the MariaDB community. MariaDB is a technocracy, and we want our core membership to reflect this.

The MariaDB Foundation's role is to be a steward of the MariaDB project. The Foundation also takes the responsibility of keeping the quality of the MariaDB project high. The MariaDB Foundation has assumed this stewardship from Monty Program Ab, which was the original driver until a foundation could be created.

A current list of active core contributors (MariaDB captains) can be found on Launchpad. Anyone with enough technical skill level who actively participates in the development of MariaDB can be part of this team. You don't have to work at the MariaDB Foundation, MariaDB Corporation, or at any other Foundation member company to be able to participate or commit code!

There is an active community around MariaDB that you can be part of. Their developer contributions can be found on the log of MariaDB contributors.

There have been some questions if MariaDB is a company or a community open source project. MariaDB is a community open source project because:

☛ It's driven by a non profit foundation.

☛ All code in MariaDB is open source. The MariaDB Foundation does not and does not intend to release any closed source modules to MariaDB. The same goes for companies which are members of the Foundation.

☛ Anyone who matches the criteria of a MariaDB captain can get commit rights to the MariaDB code base. There are many different companies and individuals among them.

☛ Anyone can contribute articles to the MariaDB Knowledge Base with very few restrictions.

☛ The MariaDB Foundation manages the MariaDB trademark, but gives broad rights to it to others.

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25⟩ Explain me why Does Mariadb 10.2 Use Innodb Instead Of Xtradb?

Keeping InnoDB (or XtraDB) up to date with MySQL (Percona) is a complex task. It took us more than half a year to migrate from InnoDB-5.6 to InnoDB-5.7 in 10.2. Doing it again for XtraDB would probably have required only slightly less than this. For us to embark on such project, it must bring significant benefits to our users.

XtraDB had many great improvements over InnoDB in 5.1 and 5.5. But over time, MySQL has implemented almost all of them. InnoDB has caught up and XtraDB is only marginally better. Not enough to justify a multi-month merge that would delay 10.2-GA for everyone.

In particular, the only real improvement that XtraDB 5.7 seems to have is for a write-intensive I/O-bound workload, where innodb_thread_concurrency control is disabled.

With a proper innodb_thread_concurrency, XtraDB is only marginally better. We didn't want to delay 10.2-GA by up to half a year for the sake of those few users who have write-intensive I/O-bound InnoDB workload and don't know how to configure innodb_thread_concurrency.

Note, we still consider incorporating XtraDB optimizations, but as patches, rather than XtraDB as a whole, which no longer has numerous all-over-the-code improvements.

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26⟩ Tell us what is an aggregate function? How many types of aggregate functions in MariaDB?

In relational database management system, aggregate functions are the functions where the values of multiple rows are grouped together as input on certain criteria and provide a single value of more significant meaning such as a list, set etc.

Following is a list of aggregate function in MariaDB:

☛ MariaDB COUNT Function

☛ MariaDB SUM Function

☛ MariaDB MIN Function

☛ MariaDB MAX Function

☛ MariaDB AVG Function

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27⟩ Tell us what is a procedure or a stored procedure in database?

Procedures are sort of functions in a database. Procedures are created when you want to perform a task repetitively.

MariaDB procedure is a stored program that is used to pass parameters into it. It does not return a value like a function does.

You can create and drop procedures like functions.

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28⟩ Do you know what is the use of TRUNCATE statement? How is it different from DELETE statement?

TRUNCATE TABLE statement is used to delete a table permanently. It deletes all the records from the table.

Syntax:

TRUNCATE [TABLE] [database_name.]table_name;

Difference between DELETE and TRUNCATE statement:

☛ DELETE statement is used to remove one or more columns from a table as well as whole table. On the other hand, TRUNCATE TABLE statement is used to delete the whole table permanently.

☛ TRUNCATE TABLE statement is same as DELETE statement without a WHERE clause.

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30⟩ Explain me gui/workbench For Mariadb Aria?

There are many GUI tools that work with MariaDB, such as Webyog/SQLyog, HeidiSQL, dbForge Studio for MySQL, and of course, MySQL Workbench.

We know some tools have received requests and/or are working to add support for MariaDB and Aria-specific features (SQLyog, for example). Until your preferred GUI tool supports MariaDB and Aria-specific features directly, most of the tools provide a mechanism for editing and executing custom SQL code.

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31⟩ Explain me what is the use of DELETE statement in MariaDB?

The MariaDB DELETE statement is used to delete one or more records from the table in the database. It can be used to delete records from the table as well the whole table if you use it without WHERE condition.

Syntax:

DELETE FROM table

[WHERE conditions]

[ORDER BY expression [ ASC | DESC ]]

[LIMIT number_rows];

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32⟩ Please explain what Is Mariadb Galera Cluster?

MariaDB Galera Cluster is a synchronous multi-master cluster for MariaDB. It is available on Linux only, and only supports theXtraDB/InnoDB storage engines (although there is experimental support for MyISAM - see the wsrep_replicate_myisam system variable).

Starting with MariaDB 10.1, the wsrep API for Galera Cluster is included by default. This is available as a separate download for MariaDB 10.0 and MariaDB 5.5.

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36⟩ Do you know what else do they consider themselves, a sysadmin or a developer?

Allow them to talk about their experiences and how it has shaped their career.

Historically MySQL DBA are created out of their work experience. Some are focused on System administration while others are Web Developers, sometimes they are all of the above. Either way they now have a focus on the MySQL database and you might be able to use that experience to your advantage.

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39⟩ How to uninstall Mariadb On Osx?

or MariaDB 5.3.x then you can uninstall MariaDB with:

sudo make uninstall

If you compiled and installed MariaDB 5.5.x or higher then there is no 'make uninstall'. However, after doing a 'sudo make install' to install MariaDB there will be an 'install_manifest.txt' file at the top level of the source dir. Remove all of the files listed in it and everything you installed will be gone.

On Linux the default is to place everything under '/usr/local/mysql/' so removing that directory is enough to uninstall MariaDB. If you customized the install directory, or if MacOS has a different default then it will be different. In any case the 'install_manifest.txt' file will have the locations.

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