Recovering from mydumper using myloader


Let’s face it, backing up and restoring databases can be a real pain. But don’t worry, we got your back! In this article, we’ll guide you through the process of recovering from a Mydumper backup using Myloader. We’ll explain what Mydumper and Myloader are, their benefits, and most importantly, how to get your database up and running again.

Mydumper and Myloader: A Dynamic Duo

Mydumper is a high-performance MySQL data dump utility that allows you to create fast and reliable backups of your databases. It does this by using a multi-threaded approach, making it much faster than the traditional mysqldump tool.

On the flip side, we have Myloader, Mydumper’s trusty sidekick. This utility is designed to load the backups created by Mydumper back into your MySQL database. Myloader also uses a multi-threaded approach, so you can get your databases up and running in no time.

Installing Mydumper and Myloader

Before we dive into the process, let’s make sure you have Mydumper and Myloader installed on your system. Both tools can be installed using package managers like apt or yum, depending on your Linux distribution. Here’s a quick rundown on how to get them installed:

On Debian/Ubuntu:

sudo apt-get update
sudo apt-get install mydumper myloader


sudo yum install epel-release
sudo yum install mydumper myloader

Now that you’ve got both tools installed, let’s move on to creating a backup with Mydumper.

Creating a Backup with Mydumper

Backing up your MySQL database with Mydumper is pretty straightforward. Here’s a basic example of how to create a backup:

mydumper -u root -p your_password -B your_database -o backup_directory

Let’s break down the command:

  • -u root specifies the MySQL user.
  • -p your_password is the password for the MySQL user.
  • -B your_database is the name of the database you want to back up.
  • -o backup_directory is the directory where you want to store the backup.

You can also customize the backup process by adjusting the number of threads, row chunk sizes, and other options. Check out the Mydumper documentation for more details.

Recovering a Database with Myloader

Now that you have a backup, let’s recover your database using Myloader. The process is similar to creating a backup, but with a few differences. Here’s a basic example of how to recover a database:

myloader -u root -p your_password -B your_database -d backup_directory

The command is similar to the Mydumper command, with a few changes:

  • -d backup_directory is the directory containing the backup files.

Again, you can customize the recovery process by adjusting the number of threads and other options. Check out the Myloader documentation for more details.

Common Myloader Issues and How to Troubleshoot Them

Sometimes, things don’t go as planned, and you might run into some issues while recovering your database with Myloader. Don’t panic! Here are a few common issues and how to troubleshoot them:

Error: “Unknown database ‘your_database'”

This error occurs when the specified database doesn’t exist in your MySQL server. To fix this, simply create the database before running the Myloader command:

mysql -u root -p your_password -e "CREATE DATABASE your_database;"

Error: “Access denied for user ‘root’@’localhost'”

This error indicates that the specified MySQL user doesn’t have the necessary privileges to perform the recovery. To grant the required privileges, log in to MySQL as an administrator and run the following command:

GRANT ALL PRIVILEGES ON your_database.* TO 'root'@'localhost';

Slow recovery process

If you find that the recovery process is taking longer than expected, consider increasing the number of threads used by Myloader. You can do this by adding the --threads option to your Myloader command:

myloader -u root -p your_password -B your_database -d backup_directory --threads=8

Adjust the number of threads based on your system’s resources and performance.

Incomplete or corrupt backup files

In some cases, you might encounter issues with the backup files themselves. If you suspect that the backup files are incomplete or corrupt, you’ll need to create a new backup using Mydumper and retry the recovery process with the new backup.


And there you have it! Now you know how to recover your MySQL database from a Mydumper backup using Myloader. Remember, always test your backups and recovery processes to ensure they’re working correctly. Regularly backing up and knowing how to restore your databases can save you a ton of headaches down the road.

Now go forth and conquer those backups!

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