“MySQL server has gone away” can occur when a connection is closed after a timeout, when a client sends a packet that is too large, or when the connection is otherwise lost.
- Identify whether the error follows a long idle period or a specific large query/import.
- If it occurs during a large import, check for
max_allowed_packetor packet-size errors. - Reduce oversized inserts/import batches when possible.
- Check application logs for the query or operation immediately before the disconnect.
- Retest with a smaller data set to determine whether size is the trigger.
Do not assume every “server has gone away” message has the same cause; MySQL documents several different conditions that can produce it.
