MySQL error 1047 appears when the server receives an unknown or out-of-order command, usually caused by protocol mismatch, wrong client version, or corrupted connection.
MySQL Error 1047: ER_UNKNOWN_COM_ERROR occurs when the server flags a client command as unknown, often due to a protocol or version mismatch. Upgrade or align client and server versions, then reconnect with a clean session to resolve the issue.
Unknown command
The message "Unknown command" means the MySQL server could not recognize the first packet sent by the client after connection. The server closes the link and returns SQL State 08S01, signaling a protocol violation.
This error usually surfaces when mixing different MySQL client libraries or when a network device alters packets.
Although labeled a connection problem, it can also appear mid-session if the stream becomes corrupted.
Protocol mismatch tops the list. A newer client may speak a command the old server does not understand, or the reverse.
SSL negotiation errors can also corrupt the initial handshake packet.
Network appliances that compress or inspect traffic occasionally reorder or truncate packets, triggering the server’s unknown command response.
First verify that client and server share a compatible major version. Reinstall or upgrade the MySQL client libraries if they differ by more than one release.
If versions match, test connectivity with mysql --protocol=tcp to bypass shared-memory or socket bugs.
Disable SSL temporarily to isolate encryption issues.
Dumping a database with an old mysqldump against a new server often fails with 1047. Installing the matching mysql-client package resolves it.
In containerized stacks, the application image may include libmysql 5.6 while the host runs MySQL 8.0. Rebuild the image with mysql-client-8.0 to fix the mismatch.
Standardize client and server versions through package management or Docker images.
Enforce version pinning in CI pipelines to prevent drift.
Monitor connection logs for aborted handshakes. Early detection allows teams to align binaries before production outages occur.
Errors 2006 (MySQL server has gone away) and 2013 (Lost connection) may follow 1047 when the client retries improperly. Align protocol versions and tune wait_timeout to mitigate these cascades.
.
No. The error targets the connection layer, not the storage engine. Your data remains intact.
Ignoring it masks deeper version or network issues that will resurface. Fix the mismatch instead.
mysqldump ships with its own libmysql. If that library is older than the server, 1047 appears during dump.
Galaxy bundles an up-to-date MySQL client and alerts you when the server version differs, reducing protocol mismatches.
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