MySQL Error: /usr/sbin/mysqld: error while loading shared libraries: liblz4.so.1: cannot open shared object file: Permission denied (Ubuntu)

• /usr/sbin/mysqld: This is the path to the MySQL server executable on Ubuntu systems.
• error while loading shared libraries: This indicates that MySQL is trying to load additional libraries it needs to function, but it's encountering an error during this process.
• liblz4.so.1: This is the specific library that MySQL is having trouble loading. liblz4.so.1 is likely part of the lz4 library, which provides data compression functionality.
• cannot open shared object file: Permission denied: This is the crux of the error. It means that MySQL doesn't have the necessary permissions to access the liblz4.so.1 library file.

Potential Causes and Solutions:

1. Incorrect Permissions:

   • The most likely cause is that the permissions on the liblz4.so.1 file are incorrect. MySQL might not have read or execute permissions for the file.
   • Solution:

2. Missing or Corrupted Library:

   • It's possible that the liblz4.so.1 file is missing altogether or is corrupted.
   • Solution:

3. Conflicting Library Versions:

   • In rare cases, there might be a conflict between different versions of the liblz4 library or its dependencies.
   • Solution:

Additional Tips:

• If you're unsure about modifying file permissions, consult your system administrator for guidance.
• After making changes, try restarting the MySQL service with sudo systemctl restart mysql (or mariadb if you're using MariaDB).
• If the issue persists, provide more details about your system and MySQL setup for further assistance.

locate liblz4.so.1

This command uses the locate utility to search for the liblz4.so.1 file on your system. It can help you identify the exact path to the library, which you can then use in the permission correction command.

Fixing File Permissions (Assuming you know the location):

sudo chmod +rX /path/to/liblz4.so.1

Important: Replace /path/to/liblz4.so.1 with the actual location of the liblz4.so.1 file obtained from the previous command (or if you already know it).

This command uses sudo to run it with administrator privileges, followed by chmod +rX which modifies the permissions on the file. The +r grants read permission, and +X grants execute permission, both of which are necessary for MySQL to access the library.

Reinstalling Library Package (assuming Ubuntu/Debian):

sudo apt-get install --reinstall liblz4

This command uses apt-get (the package manager for Ubuntu/Debian) with the --reinstall flag to reinstall the liblz4 package. This can potentially fix any missing or corrupted library files.

Restarting MySQL Service (after making changes):

sudo systemctl restart mysql  # For MySQL
sudo systemctl restart mariadb  # For MariaDB (if applicable)

This command uses systemctl restart along with mysql or mariadb (depending on your specific database server) to restart the service after you've made changes (like fixing permissions or reinstalling the library). This allows the changes to take effect.

1. Check AppArmor Profile (if applicable):

   • AppArmor is a security feature in Ubuntu that can restrict application access to certain resources. If AppArmor is configured for MySQL, it might be blocking access to liblz4.so.1.

2. Verify Shared Library Path (Advanced):

   • In rare cases, the system might have an incorrect path configured for shared libraries. This can happen if you have multiple library directories or custom configurations.
   • Solution:

3. Consider Reinstalling MySQL (Last Resort):

   • If all else fails, consider reinstalling MySQL. This can potentially fix any deeper configuration issues or missing dependencies.
   • Solution: