MariaDB How to remove completely a corrupted database?

You need to optimise mysql configuration to better handle mysql upgrades for such large forums Difference between optimised verus non-optimised mysql config can be huge for large forum upgrades !!!!

so you started on CLI upgrade, then started web browser /install upgrade ? did you check if mysql processes were running for previous CLI upgrade ? Have you confirmed with xenforo support if moving from CLI upgrade to browser will retain it's state/position and start off where CLI upgrade left off ??

generally CLI upgrades will be faster than web browser, so I wouldn't use web browser upgrade and stick with CLI upgrade.

Probably will corrupt some mysql data if mysql processes are still running

probably corrupt innodb tables so you won't be able get that info

Centmin Mod is provide as is, so short of scripted related bugs or issues, any further optimisation to the web stack components - nginx, php-fpm, mariadb mysql, csf firewall etc or web app specific configurations are left to the Centmin Mod user to deal with. So I do not provide any free support for such as MySQL database corruption, repair and recovery. You'd want to hire someone if you are not 100% sure how to fix MySQL database corruption or do repair and recovery.

However, Centmin Mod users are free to help each other out and ask questions or give answers on this community forum. My hopes are that this community forum evolves so that more veteran long time Centmin Mod users help new Centmin Mod users out

If you did mysql restart/reboot or MySQL crashed in the middle of mysql operation i.e. processing an alter table and basically corrupted the database table(s) - producing an intermediate orphaned innodb table(s).

See MySQL :: MySQL 5.7 Reference Manual :: 14.21.3 Troubleshooting InnoDB Data Dictionary Operations. Example below but the rest of instructions and steps after are left to you to figure out. You'd want to hire someone if you are not 100% sure how to fix MySQL database corruption or do repair and recovery.

You can check using this command for orphaned tables beginning with #sql in their names.

Code (Text):

mysql -e "SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE '%#sql%';"

Look for table names that begin with #sql. If the original table resides in a file-per-table tablespace (Centmin Mod MariaDB does use file-per-table), the tablespace file (the #sql-*.ibd file) for the orphan intermediate table should be visible in the database directory.

To remove an orphan intermediate table, perform the following steps:

1. In the database directory, rename the #sql-*.frm file to match the base name of the orphan intermediate table:
   
   
   Code (Text):

   mv #sql-36ab_2.frm #sql-ib87-856498050.frm

   
   
   Note
   If there is no .frm file, you can recreate it. The .frm file must have the same table schema as the orphan intermediate table (it must have the same columns and indexes) and must be placed in the database directory of the orphan intermediate table.
   
   
2. Drop the orphan intermediate table by issuing a DROP TABLE statement, prefixing the name of the table with #mysql50# and enclosing the table name in backticks. For example:
   
   
   Code (Text):

   mysql > DROP TABLE `#mysql50##sql-ib87-856498050`;

   
   The #mysql50# prefix tells MySQL to ignore file name safe encoding introduced in MySQL 5.1. Enclosing the table name in backticks is required to perform SQL statements on table names with special characters such as “#”.

 

it would show in /var/lib/mysql/yourdbname/ directory too.

 

Google for how to re-create frm files for innodb orphaned tables

or

 

now that's weird indeed !