Mysql – completely remove mariadb database and root password

mariadbMySQL

The system is Fedora 32. Mariadb was installed and operational; it is now necessary to reinitialize Mariadb and all data and users.

I removed mariadb-server and mariadb and erased /etc/my.cnf and my.cnf.d. I then reinstalled mariadb and mariadb-server and ran the mysql_secure_installation script. It found the original root password but otherwise completed normally.

I then logged into mariadb. I expected to find the users from the original installation had been removed; however they had not.

show databases; shows the original tables. They were not removed.

select * from mysql.user; showed the original users.

How can mariadb be completely removed including all users, data, and passwords?

Best Answer

You need to delete the data in your datadir, since that is where this is stored. The default location is /var/lib/mysql/. Shut down MariaDB and delete everything inside the datadir without deleting the datadir itself (as you want to avoid having to recreate the directory with exactly the right permissions):

sudo systemctl stop mariadb
sudo rm -rf /var/lib/mysql/*

Then use mysql_install_db to re-initialise the datadir.

Related Solutions

MySql 5.6 error (Table ‘thesql.user’ doesn’t exist) when started as a daemon

I've conquered such issue before, pay attention that there's an original data dir existed in x:/your_mysql_5.6_install_dir/data.

if you have defined datadir=xxx in my.ini, and the path is not the one x:/your_mysql_5.6_install_dir/data, please do the following things:

copy x:/your_mysql_5.6_install_dir/data to the destination folder.
start MySQL

e.g. if you have defined: [mysqld] basedir=C:/mysql-5.6.43-winx64 datadir=C:/ProgramData/MySQL/MySQL 5.6 server/data

you need to copy C:/mysql-5.6.43-winx64/data to C:/ProgramData/MySQL/MySQL 5.6 server/data

then start your MySQL.

this has been described in https://dev.mysql.com/doc/refman/5.6/en/windows-create-option-file.html:

If you would like to use a data directory in a different location, you should copy the entire contents of the data directory to the new location. For example, if you want to use E:\mydata as the data directory instead, you must do two things:

1) Move the entire data directory and all of its contents from the default location (for example C:\Program Files\MySQL\MySQL Server 5.6\data) to E:\mydata.

2) Use a --datadir option to specify the new data directory location each time you start the server.

Mysql – NTFS Filesystem Fragmentation issue occur after migrating thesql 5.6 database to mariadb 10.2

This is a bug, which I filed and fixed, based on this question. BTW, we do have a bug system too, do not hesitate to use it directly.

Here is the bug report. https://jira.mariadb.org/browse/MDEV-13941

Basically, fragments are created because sparse file is being extended. The fix is not to create sparse files, unless user wants a table with page compression (which is an exotic feature that not many people would use). The fix will appear in the next 10.2 (i.e 10.2.10), mid-end October.

However, just the upgrade to 10.2.10 won't automatically fix the problem for existing tables. There is something else you need to do prior to installation of 10.2.10

Stop the server
Unset the "sparse flag" on .idb files. in elevated command prompt, type
```
fsutil sparse setflag C:\path\to\table.ibd 0
```
Defragment file with contig (or other tools)

Best Answer

Related Solutions

MySql 5.6 error (Table ‘thesql.user’ doesn’t exist) when started as a daemon

Mysql – NTFS Filesystem Fragmentation issue occur after migrating thesql 5.6 database to mariadb 10.2

Related Question