Error 2065 appears when a MySQL 8.0.21+ client requests the deprecated compressed protocol while using the new asynchronous client protocol.
CR_DEPRECATED_COMPRESSION_NOT_SUPPORTED happens when a MySQL 8.0.21 or later client enables the old compressed protocol while using the asynchronous protocol. Remove the compress flag or fall back to the synchronous protocol to resolve the error.
Compression protocol not supported with asynchronous protocol CR_DEPRECATED_COMPRESSION_NOT_SUPPORTED was added in 8.0.21.
Error 2065 is raised by the MySQL client library when it detects a request for the legacy compressed protocol together with the asynchronous client protocol. Since 8.0.21, MySQL removed support for compression in async mode, triggering CR_DEPRECATED_COMPRESSION_NOT_SUPPORTED.
The message signals a client-side problem, so changing server variables will not help. You must adjust connection options in the client, driver, or application code.
The error occurs during the handshake phase.
Any client, connector, or ORM that sets the MYSQL_CLIENT_COMPRESS flag (or the equivalent configuration property) while also opting into the asynchronous protocol will fail immediately.
Commonly affected environments include C API applications compiled against libmysqlclient 8.0.21+, Java apps using MySQL Connector/J with useCompression=true and enableAsyncProtocol=true, and Python MySQL Connector using compress=True with raw_as_string=True.
Because the handshake never completes, no SQL is executed, causing outages in services that rely on MySQL.
Removing the incompatibility restores connectivity and prevents downtime.
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No. MySQL permanently removed support in 8.0.21. You must choose between compression and async.
The error depends on the client library version, not the server. A 5.7 server will still throw the error if the client is 8.0.21+.
TLS compression is unrelated. Only the deprecated MySQL protocol compression is blocked.
Galaxy’s connection manager defaults to async without compression, preventing this error. If you import an old DSN with compression enabled, Galaxy flags the conflict before executing queries.
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