Bug #111697 MySQL Java Driver is not able to connect to MariaDB after upgrading to 11.x.x

• Submitted: 8 Jul 2023 10:24
• Modified: 10 Jul 2023 13:14
• Reporter: kyngs kyngs
• Status: Unsupported
• Category: Connector / J
• Severity: S2 (Serious)
• OS: Any
• CPU Architecture: Any
• Tags: java, MariaDB, MySQL

[8 Jul 2023 10:24] kyngs kyngs

Description:
When I attempt to connect using the "com.mysql.cj.jdbc.Driver" the driver fails to connect with the following exception: "CJException: Unknown system variable 'transaction_isolation'"
I suppose this is because the variable "transaction_isolation" does not exist in MariaDB and is replaced by "tx_isolation"? Perhaps the driver failed to detect that it is connecting to a MariaDB server, not MySQL? 

The only workaround I found is downgrading MariaDB to "10.11.4"

How to repeat:
Install MariaDB 11.0.2
Attempt to connect with MySQL JDBC driver 8.0.33
Observe

Suggested fix:
The driver should detect that it is connecting to a MariaDB server and use the correct variable.

[10 Jul 2023 6:24] Frederic Descamps

Hello, 

MySQL and MariaDB are two distinct projects that have diverged in development.

MariaDB is not a drop-in replacement for MySQL anymore and you can not expect that our connectors will be compatible with MariaDB.

Best regards,

[10 Jul 2023 7:49] kyngs kyngs

Hi Frederic,
thanks for the quick reply. MySQL J driver has always been compatible with MariaDB. Dropping this compatibility on MariaDB version 11 is quite unfortunate because many people depend on this.

[10 Jul 2023 13:14] MySQL Verification Team

Hello,

Thank you for the bug report.
As Frederic explained, our connectors are not compatible with MariaDB. Unsupported!

Regards,
Ashwini Patil

[6 Nov 2023 13:30] MySQL Verification Team

Bug #112960 marked as duplicate of this one.