Couldn't start mysql even when there is no services using port 3306

问题

I have an issue with mysql XAMPP. When I try to start mysql, it failed and here's the error message that I copied from mysql_error.log.

InnoDB: using atomic writes.
2020-01-25 19:44:16 0 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions
2020-01-25 19:44:16 0 [Note] InnoDB: Uses event mutexes
2020-01-25 19:44:16 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-01-25 19:44:16 0 [Note] InnoDB: Number of pools: 1
2020-01-25 19:44:16 0 [Note] InnoDB: Using SSE2 crc32 instructions
2020-01-25 19:44:16 0 [Note] InnoDB: Initializing buffer pool, total size = 16M, instances = 1, chunk size = 16M
2020-01-25 19:44:16 0 [Note] InnoDB: Completed initialization of buffer pool
2020-01-25 19:44:16 0 [Note] InnoDB: 1 out of 1 rollback segments are active.
2020-01-25 19:44:16 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-01-25 19:44:16 0 [Note] InnoDB: Setting file 'C:\xampp\mysql\data\ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-01-25 19:44:16 0 [Note] InnoDB: File 'C:\xampp\mysql\data\ibtmp1' size is now 12 MB.
2020-01-25 19:44:16 0 [Note] InnoDB: 10.4.8 started; log sequence number 34888; transaction id 7
2020-01-25 19:44:16 0 [Note] InnoDB: !!! innodb_force_recovery is set to 3 !!!
2020-01-25 19:44:16 0 [Note] InnoDB: Loading buffer pool(s) from C:\xampp\mysql\data\ib_buffer_pool
2020-01-25 19:44:16 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-01-25 19:44:16 0 [Note] InnoDB: Buffer pool(s) load completed at 200125 19:44:16
2020-01-25 19:44:16 0 [Note] Server socket created on IP: '::'.

The following solutions I have tried:

1. Delete ibdata1 in data folder.
2. Added innodb_force_recovery = 3 below mysqld in my.ini

When I try to start MySql module in XAMPP Control Panel. I received the following error message.

[mysql] Status change detected: stopped [mysql] Error: MySQL shutdown unexpectedly. [mysql] This may be due to a blocked port, missing dependencies, [mysql] improper privileges, a crash, or a shutdown by another method. [mysql] Press the Logs button to view error logs and check [mysql] the Windows Event Viewer for more clues [mysql] If you need more help, copy and post this [mysql] entire log window on the forums

Here is what I got from Event Viewer:

Fatal error: Can't open and lock privilege tables: Incorrect file format 'roles_mapping'

回答1:

Deleting ibdata1 has the effect of throwing away all your data. I hope that either you are just starting, or you have a backup.

Initializing buffer pool, total size = 16M

That is terribly tiny. Change it in my.cnf to, say, 200M.

回答2:

i had the same problem when i installed the xampp in E drive.Installing in to C solved the problem for me

来源：https://stackoverflow.com/questions/59908839/couldnt-start-mysql-even-when-there-is-no-services-using-port-3306