When importing large MySQL database files, you may encounter the “MySQL server has gone away” or “Packet too large” error. This usually happens when the file size exceeds the server’s allowed packet limit.
This issue is common during database migrations, backups, or restoring large .sql dump files. If your MySQL configuration is not optimized for large imports, the process will fail midway.
By default, MySQL limits the size of data packets it can process at once. When you try to upload a database file larger than this limit, the server automatically stops the operation.
Understanding this error is essential for developers working with large databases in local environments like XAMPP or on live servers. Proper configuration can easily resolve the issue.
Common Causes
Below are the main reasons why this MySQL error appears:
Low max_allowed_packet Value
The default max_allowed_packet size in MySQL (especially version 5.6) is only 4MB. Large SQL dump files exceed this limit.
Large Database Import File
When importing big .sql files containing heavy data tables, images (BLOBs), or large inserts, MySQL cannot process them due to packet restrictions.
Server Configuration Not Updated
Sometimes configuration files like my.cnf or my.ini are not properly updated, or the MySQL service is not restarted after changes.
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