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Description

This error indicates that the MySQL client cannot establish a connection to the local MySQL server process using a Unix domain socket file. It commonly occurs when the server is not running, the socket file is misconfigured or missing, or due to permission issues with the socket.

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Error Message

Can't connect to local MySQL server through socket '%s' (%d)

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Known Causes

4 known causes

⚠️

MySQL Server Not Running

The MySQL server process is not active on the local machine, preventing any client connections via socket.

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Incorrect Socket File Path

The MySQL client is configured to use a socket file path that does not match the path configured for the server.

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Missing or Corrupted Socket File

The Unix domain socket file, crucial for local connections, is either absent from its expected location or has become corrupted.

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Socket File Permissions

The operating system user attempting to connect lacks the necessary read/write permissions for the socket file or its containing directory.

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Solutions

5 solutions available

1. Check MySQL is Running easy

Verify MySQL server is started

1

Check MySQL status

sudo systemctl status mysql
# or
sudo service mysql status

2

Start MySQL if stopped

sudo systemctl start mysql
# or
sudo service mysql start

3

On Windows

net start MySQL80
# or check Services panel

2. Fix Socket File Location medium

Correct socket path in configuration

1

Find actual socket location

sudo find / -name "mysql.sock" 2>/dev/null
# or
mysqladmin variables | grep socket

2

Specify socket in connection

mysql -u root -p --socket=/var/run/mysqld/mysqld.sock

3

Create symlink if needed

sudo ln -s /var/run/mysqld/mysqld.sock /tmp/mysql.sock

4

Or configure in my.cnf

[client]
socket=/var/run/mysqld/mysqld.sock

[mysqld]
socket=/var/run/mysqld/mysqld.sock

3. Fix Socket Permissions medium

Ensure socket file is accessible

1

Check socket permissions

ls -la /var/run/mysqld/mysqld.sock

2

Fix directory permissions

sudo mkdir -p /var/run/mysqld
sudo chown mysql:mysql /var/run/mysqld
sudo chmod 755 /var/run/mysqld

3

Restart MySQL

sudo systemctl restart mysql

4. Use TCP Instead of Socket easy

Connect via TCP/IP instead of socket

1

Use 127.0.0.1 instead of localhost

# Socket connection (default for localhost):
mysql -u root -p -h localhost

# TCP connection:
mysql -u root -p -h 127.0.0.1

2

In connection string

// Using 127.0.0.1 forces TCP:
mysql://user:pass@127.0.0.1:3306/database

5. Fix After Crash or Improper Shutdown medium

Clean up stale socket file

1

Remove stale socket

sudo rm /var/run/mysqld/mysqld.sock
sudo rm /var/run/mysqld/mysqld.sock.lock

2

Check for stuck processes

ps aux | grep mysql
# Kill if necessary
sudo kill -9 <pid>

3