MySql FAQ: How to avoid errors when migrating data

With the popularization of the Internet, data storage and management have become essential infrastructure for every enterprise. As one of the most basic management systems in the database, MySql plays a very important role in the database. Migrating data is one of the important operations for MySql users, but many users will encounter various errors when migrating data. In this article, we will solve some common MySql migration data errors to help users better complete data migration.

1. Error: “Access denied for user”

First of all, this is one of the most common problems when migrating data. The reason for this error is that the user connecting to the MySql database does not have access rights to the target database. To solve this problem, you need to check the following aspects:

• For MySql server, make sure remote connections are enabled on the MySql server.
• Make sure the username and password entered are correct.
• Make sure the user has the correct permissions, such as access to the database to be imported.

2. Error: "Lock wait timeout exceeded"

This is another common MySql migration error. The root cause of this error is that a running transaction is waiting for a lock. In this case, you can solve the problem by checking the following aspects:

• First, make sure that in the MySql configuration file, the value of maximum_wait_timeout is not too low. If this value is too low, the waiting time for the lock will be shortened, resulting in lock timeout.
• Secondly, you can use the SHOW PROCESSLIST command to view the list of currently running processes. Find the process that is locking the table and clean or optimize it.
• You can try to restore the lock process by increasing the lock timeout, but this is not the best solution.

3. Error: “Table ‘#sql-xxx_xxxxxx’ already exists”

This error indicates that the operation of creating a new table has the same name as an existing table. If you encounter this problem, you can try the following methods:

• Modify the name of the new table to avoid having the same name as an existing table.
• Delete the existing table so that it can be re-created.
• If the existing table is a table you don’t need, you can delete it directly.

4. Error: "The total number of locks exceeds the lock table size"

This error indicates that the total number of locks in the lock table has reached the maximum allowed by the lock table value. In order to solve this problem, you can consider the following methods:

• If feasible, increase the size of the lock table.
• You can reduce the number of locks by reducing the size of the transaction interval or recursively updating, so as to shorten the lock time.
• You can use a locked table more efficiently by trying to update rows instead of the entire table.

5. Error: "Error on rename of './database/table' to './database/#sql2-xxx-xx' "

This error is usually expressed in There was a problem while renaming the table. If you encounter this problem, you can try the following methods:

• Make sure that no two tables have the same name.
• Make sure that the table to be renamed is completely closed (no other processes or threads are using the table).
• You can try to destroy the table and then rebuild it.

Finally, solving these common MySql migration data errors requires an in-depth understanding of some basic knowledge of MySql and database management skills. If you encounter other problems, please do not hesitate to contact the MySql official team in time, and they will provide more in-depth help and support. I hope this article can help you better manage MySql database!

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