Logging Errors to File in mysqldump

Using the mysqldump command with the --log-error=name option allows you to specify a file where MySQL errors encountered during the dump operation will be logged. This is particularly useful for troubleshooting and monitoring the dumping process.

Here are several examples demonstrating how to utilize this option:

Example 1: Logging errors to a specific file named dump_errors.log:

mysqldump --log-error=dump_errors.log -u username -p database_name > backup.sql

This command dumps the database database_name into backup.sql while logging any errors to dump_errors.log.

Example 2: Using a full path for the error log file:

mysqldump --log-error=/var/log/mysql/dump_errors.log -u username -p database_name > backup.sql

Here, errors are logged to /var/log/mysql/dump_errors.log during the database dump.

Example 3: Logging errors in the current directory with a timestamped file:

timestamp=$(date +"%Y%m%d_%H%M%S")
mysqldump --log-error="error_log_${timestamp}.txt" -u username -p database_name > backup.sql

This script creates an error log file named with a timestamp (e.g., error_log_20240622_154512.txt) in the current directory.

Example 4: Redirecting errors to a separate directory:

mkdir /var/log/mysql_errors
mysqldump --log-error="/var/log/mysql_errors/dump_errors.log" -u username -p database_name > backup.sql

Here, errors are logged to /var/log/mysql_errors/dump_errors.log, stored in a directory specifically for MySQL errors.

Example 5: Using a relative path for the error log file:

mysqldump --log-error="logs/dump_errors.log" -u username -p database_name > backup.sql

This command logs errors to logs/dump_errors.log relative to the current working directory.

Example 6: Logging errors with a custom descriptive filename:

mysqldump --log-error="backup_errors_$(date +%Y%m%d).log" -u username -p database_name > backup.sql

Here, errors are logged to a file named backup_errors_20240622.log (the current date) during the database dump process.

Example 7: Logging errors with a dynamically generated filename based on script execution:

logfile="mysqldump_errors_$(date +\%Y\%m\%d_\%H\%M\%S).log"
mysqldump --log-error="$logfile" -u username -p database_name > backup.sql

This script creates a unique error log file each time the command is executed, using the current timestamp.

Example 8: Redirecting errors to a network-mounted directory:

mysqldump --log-error="//server/share/dump_errors.log" -u username -p database_name > backup.sql

Here, errors are logged to //server/share/dump_errors.log, which is a network share accessible to the MySQL server.

Example 9: Logging errors with a verbose descriptive filename:

mysqldump --log-error="backup_errors_$(date +\%Y-\%m-\%d_\%H-\%M-\%S).log" -u username -p database_name > backup.sql

This command logs errors to a file named backup_errors_2024-06-22_15-45-32.log, incorporating both date and time in the filename.

Example 10: Using a temporary directory for error logs:

tmpdir=$(mktemp -d)
mysqldump --log-error="$tmpdir/dump_errors.log" -u username -p database_name > backup.sql
rm -rf "$tmpdir"

This script creates a temporary directory, logs errors to dump_errors.log within that directory, and cleans up the temporary files after completion.

To verify whether the mysqldump command executed successfully with error logging, check the specified error log file (e.g., dump_errors.log). If the file exists and contains entries, it confirms that errors were logged during the dump process.

Also check similar articles.

Locking Tables for Read in mysqldump
Locking All Tables Across Databases in mysqldump
Setting Line Terminator in mysqldump Output
Using INSERT IGNORE Statements in mysqldump
Including Master Host and Port in mysqldump Output (Deprecated)