1. Please explain why Is The Project Called Mariadb?
The 'MySQL' name is trademarked by Oracle, and they have chosen to keep that trademark to themselves. The name MySQL (just like the MyISAM storage engine) comes from Monty's first daughter "My". MariaDB continues this tradition by being named after his younger daughter, Maria.
2. Tell me a tool that helps with replication integrity checking?
Percona's pt-table-checksum is the preventative tool to use
It can build checksums of all your tables, and then propagate those checksums through replication to the slave.
3. Do you know how To Change Innodb_page_size?
No need for a fresh install.
Just export your data, move or delete the system database (ibdata1) and the log files (ib_logfile0 & ib_logfile1), set innodb_page_size to either 4k or 8k, and restart MariaDB. A new XtraDB instance will be created with the smaller page size. Then you can import your data and run your tests.
4. Explain me how to create a table in MariaDB's database?
First, you have to create a database in MariaDB follows by selecting the database and then create a table by using CREATE TABLE statement.
Syntax:
CREATE TABLE table_name (column_name column_type);
5. Please explain what is the use of MariaDB DISTINCT clause?
MariaDB DISTINCT Clause is used to remove duplicates from the result when it is used with SELECT statement.
Syntax:
SELECT DISTINCT expressions
FROM tables
[WHERE conditions];
6. Tell us how to delete a database in MariaDB?
DROP DATABASE command is used to drop a database in MariaDB.
Syntax:
DROP DATABASE Database_name;
7. Tell us what is the usage of AVG() function in MariaDB database?
MariaDB AVG() function is used to retrieve the average value of an expression.
Syntax:
SELECT AVG(aggregate_expression)
FROM tables
[WHERE conditions];
8. Tell me what is JOIN? How many types of JOIN in MariaDB?
JOIN is used to retrieve data from two or more tables. By default JOIN is also called INNER JOIN. It is used with SELECT statement.
There are mainly two types of joins in MariaDB:
☛ INNER JOIN
☛ OUTER JOIN
Again OUTER JOIN is divided in two types:
☛ LEFT JOIN
☛ RIGHT JOIN
9. Do you know default Data Directory For Mariadb?
The data directory location is controlled by the datadir variable. Look at your /etc/mysql/my.cnf file to see where your installation of MariaDB is configured to store data. The default is /var/lib/mysql but it is often changed, like for example if you are using a RAID array.
10. Do you know how to use database in MariaDB?
USE DATABASE command is used to select and use a database in MariaDB.
Syntax:
USE database_name;
11. Please explain what is the use of LIKE clause in MariaDB?
MariaDB LIKE clause is used with SELECT, INSERT, UPDATE and DELETE statement to retrieve data when an operation needs an exact match.
Syntax:
SELECT field, field2,... FROM table_name, table_name2,...
WHERE field LIKE condition
12. Tell me what is RIGHT OUTER JOIN in MariaDB?
MariaDB RIGHT OUTER JOIN is used to return all rows from right-hand table specified in the ON condition and only those rows from the other table where the joined fields are satisfied the conditions.
MariaDB RIGHT OUTER JOIN is also called RIGHT JOIN.
Syntax:
SELECT columns
FROM table1
RIGHT [OUTER] JOIN table2
ON table1.column = table2.column;
13. Tell me what is the use of ORDER BY clause in MariaDB?
MariaDB ORDER BY Clause is used to sort the records in your result set in ascending or descending order.
Syntax:
SELECT expressions
FROM tables
[WHERE conditions]
ORDER BY expression [ ASC | DESC ];
14. Tell me which Is The Max Storage Capacity Of Version 5.5 Mariadb?
InnoDB/XtraDB tables can be up to 64TB (terabytes) in size. On top of this you can have multiple tables per database and multiple databases per server. Usually the size and space limits of your underlying storage and operating system are reached long before MariaDB's internal limits are reached.
15. Do you know how to delete a table in MariaDB's database?
DROP TABLE command is used to delete a table from a database in MariaDB. It deletes the table permanently and cannot be recovered.
Syntax:
DROP TABLE table_name ;
16. Tell me why do we use FROM clause with SELECT statement?
FROM clause is used with SELECT statement to retrieve data from the table. It is also used to join tables.
Syntax:
SELECT columns_names FROM table_name;
17. Tell me what are the major differences between MySQL 5.1 and 5.5?
☛ InnoDB Becomes Default Storage Engine
☛ Semi-Synchronous Replicatio
☛ Improved Recovery Performance
☛ InnoDB Stats in Performance Schema
☛ Multiple Buffer Pool Instances
☛ More Partitioning Options
18. 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.
19. Tell me how to create database in MariaDB?
CREATE DATBASE command is used to create database in MariaDB.
Syntax:
CREATE DATABASE Database_name;
20. Tell me how to retrieve records from a table in MongoDB database?
SELECT statement is used to retrieve records from a table in MongoDB database. You can choose, single, multiple or all records from a table by using different keywords.
Syntax:
SELECT expressions
FROM tables
[WHERE conditions];
21. Tell me what is the usage of MAX() function in MariaDB?
MariaDB MAX() function is used to retrieve the maximum value of the expression.
Syntax:
SELECT MAX(aggregate_expression)
FROM tables
[WHERE conditions];
22. 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.
23. Tell me what is the usage of MIN() function in MariaDB?
MariaDB MIN() functiuon is used to retrieve the minimum value of the expression.
Syntax:
SELECT MIN(aggregate_expression)
FROM tables
[WHERE conditions];
24. 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];
25. 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.
26. 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.
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.
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.
29. Tell us how can you change or update the already inserted records of a MariaDB table?
UPDATE statement is used to change, update or modify the existing records of a MariaDB table. It can be used with WHERE, OBDER BY and LIMIT clauses.
Syntax:
UPDATE table_name SET field=new_value, field2=new_value2,...
[WHERE ...]
30. 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.
There is no embedded version of MariaDB.
32. Do you know what is function in MariaDB? How can you create and drop function in MariaDB?
MariaDB function is a stored program that is used to pass parameters into them and return a value.
We can easily create and drop functions in MariaDB.
33. 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
34. 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.
35. 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.
