[MXS-3984] COM_CHANGE_USER from 'user' to 'user' succeeded on MaxScale yet failed on backends Created: 2022-02-04  Updated: 2022-03-21  Resolved: 2022-03-01

Status: Closed
Project: MariaDB MaxScale
Component/s: Protocol
Affects Version/s: 6.2.1
Fix Version/s: 6.2.3

Type: Bug Priority: Major
Reporter: Nilnandan Joshi Assignee: markus makela
Resolution: Fixed Votes: 1
Labels: None

Sprint: MXS-SPRINT-151

 Description   

After upgrading Maxscale from v2.5.18 to v6.2.1, I can see in maxscale.log this warnings:

2022-02-02 09:54:42   warning: (65) [MariaDBProtocol] (WritableService); COM_CHANGE_USER from 'user' to 'user' succeeded on MaxScale yet failed on backends.
 
2022-02-02 09:54:42   warning: (66) [MariaDBProtocol] (WritableService); COM_CHANGE_USER from 'user' to 'user' succeeded on MaxScale yet failed on backends.
 
2022-02-02 09:54:44   warning: (71) [MariaDBProtocol] (WritableService); COM_CHANGE_USER from 'user' to 'user' succeeded on MaxScale yet failed on backends.

We are primarily using PHP with the PDO_MYSQL driver to connect to the database. Users are generally configured statically and not changed on the fly.
> Also, what connector you are using to connect with maxscale ?
MariaDB-client-10.5.12_8-1.el8.x86_64

 Comments   
Comment by markus makela [ 2022-02-23 ]

The data that the protocol used to detect whether the COM_CHANGE_USER succeeded was not cleared out properly before the result was given to the protocol layer. This meant that if the previous query resulted in an error, the response would be considered a failure when in reality it succeeded.

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