Bug #106122 [Tencent]session track of collation_connection missing character_set_connectioB

• Submitted: 10 Jan 2022 8:25
• Modified: 10 Jan 2022 9:42
• Reporter: yuxiang jiang (OCA)
• Status: Verified
• Category: MySQL Server: Options
• Severity: S3 (Non-critical)
• Version: 5.7.36
• OS: Any
• CPU Architecture: Any
• Tags: Contribution

[10 Jan 2022 8:25] yuxiang jiang

Description:
After executing 'set collation_connection='utf8_general_ci'; ', system variable character_set_connection also changed. But server does not return character_set_connection's session track if session_track_system_variables is enabled.

How to repeat:
step 1
set global session_track_system_variables='time_zone,autocommit,character_set_client,character_set_results,character_set_connection,collation_connection';

step 2
set collation_connection='utf8_general_ci';

step 3
Check returned session track.

Suggested fix:
Check collation_connection variable when set session variables and mark character_set_connection change changed also.

[10 Jan 2022 8:30] yuxiang jiang

Contribute by Tencent

[10 Jan 2022 9:42] MySQL Verification Team

Hello yuxiang jiang,

Thank you for the report and feedback.

regards,
Umesh

[11 Jan 2022 2:15] yuxiang jiang

contribute from Tencent

(*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

Contribution: 0001-bugfix-session-track-of-collation_connection-missing.patch (application/octet-stream, text), 1.54 KiB.

[11 Jan 2022 5:02] MySQL Verification Team

Thank you for your contribution.

Sincerely,
Umesh

[12 Jan 2022 9:54] Georgi Kodinov

Thank you for trying to solve this valid problem. However this is not the right fix as it will be adding extra checks for all system variables being set. 

A better fix would be to update the tracker in a more specific place and not in the common function.