Bug #100846 MySQL .Net Client 8.0.21 failing with "same name are not supported" error
Submitted: 14 Sep 2020 15:47 Modified: 3 Feb 2021 17:20
Reporter: Robin Johnson Email Updates:
Status: Closed Impact on me:
Category:Connector / NET Severity:S1 (Critical)
Version:8.0.21 OS:Windows (Version 10)
Assigned to: CPU Architecture:Any

[14 Sep 2020 15:47] Robin Johnson
When I upgraded from MySQL Client 8.0.20 to 8.0.21 in a .net-core 3.1 application, I get this strange error when trying to call a stored procedure in AWS Aurora. If I revert to 8.0.20 - everything works fine.

MySql.Data.MySqlClient.MySqlException (0x80004005): same name are not supported.
   at MySql.Data.MySqlClient.ProcedureCache.GetProcData(MySqlConnection connection, String spName)
   at MySql.Data.MySqlClient.ProcedureCache.AddNew(MySqlConnection connection, String spName)
   at MySql.Data.MySqlClient.ProcedureCache.GetProcedure(MySqlConnection conn, String spName, String cacheKey)
   at MySql.Data.MySqlClient.StoredProcedure.CheckParameters(String spName)
   at MySql.Data.MySqlClient.StoredProcedure.Resolve(Boolean preparing)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)

How to repeat:
Download Nuget 8.0.21 MySQL client in application.
[15 Sep 2020 6:05] MySQL Verification Team
Hello Robin Johnson,

Thank you for the report and feedback.
Imho this sounds like similar/related to Bug #100306/Bug #100683. If you think this issue is different then may I request you to please provide a simple test case(c# class, sql stored procedure create statement etc) case to reproduce this issue at our end? If you can provide more information, feel free to add it to this bug and change the status back to 'Open'.  

Thank you for your interest in MySQL.

[15 Sep 2020 13:38] Robin Johnson
Definitely not the same issue. Ginning up a full-blown isolated test case will take some effort. I'll provide later today.
[15 Sep 2020 15:02] Robin Johnson
Test Program

Attachment: Program.cs (text/plain), 2.57 KiB.

[15 Sep 2020 15:06] Robin Johnson
If the MySqlConnection.CommandType is "CommandType.Text", there is no problem.
The problem occurs (regardless of stored procedure) with CommandType.StoredProcedure.

I have added C# test program to the bug. If I downgrade back to 8.0.20, the test program works without error.
[15 Sep 2020 17:36] Robin Johnson
Here is an example stored procedure that fails with 8.0.21. Works fine 8.0.20 and MySQL Workbench. Very simple table [an ID column with three varchar(120) columns]

CREATE DEFINER=`cdapoe`@`%` PROCEDURE `find_oeauthorizationgroup`(
IN p_group_name VARCHAR(120)
SELECT * FROM oeauthorization.oeauthorizationgroup WHERE group_name=p_group_name
[16 Sep 2020 7:26] MySQL Verification Team
Thank you for the test case.
[3 Feb 2021 17:20] Gustavo Cuatepotzo
This bug has been fixed since version 8.0.22