Bug #32187 Memory leak related with MySql connector and Mono

• Submitted: 8 Nov 2007 14:57
• Modified: 3 Dec 2007 8:08
• Reporter: David Cantin
• Status: Not a Bug
• Category: Connector / NET
• Severity: S2 (Serious)
• OS: Any (Tested un Windows XP and Ubuntu 7.10)
• CPU Architecture: Any

[8 Nov 2007 14:57] David Cantin

Description:
I got the following class that leak quite much :

using System;
using System.Data;
using MySql.Data.MySqlClient;

namespace MySqlRelatedMemoryLeakTestCase {
        
public class MySqlQueryLauncher {
        
        IDbConnection dbConn; 
        
        public MySqlQueryLauncher() {

                string connectionString =
"Server=localhost;Database=mysql;User ID=user;Password=password;";
                                                
                this.dbConn = new MySqlConnection(connectionString);
                this.dbConn.Open();
                
                this.StressMySql();
        }
        
        private void StressMySql() {
                
                while(true) {
                
                        IDbCommand cmd = this.dbConn.CreateCommand();
                        cmd.CommandText = "SELECT user FROM user";
                        
                        IDataReader reader = cmd.ExecuteReader();
                        
                        while(reader.Read()) {
                                string user = (string) reader["user"];
                        }
                        
                        reader.Close();
                        cmd.Dispose();
                        
                }
        }
}

}

Let this loop run and watch the memory usage of the process...

So, maybe I'm doing something wrong or maybe there is a real leak some
where in the mono code or in the MySql one.

In this example, I use mono 1.2.4 with MySqlConnector (MySql.Data.dll)
5.0.8.1. On the server side, I got MySql 5.0.21-3ubuntu1 (default
install) on ubuntu Dapper Drake.

I have have a simple test case (a monodevelop solution) that trigger the
problem that I can send on request.

How to repeat:
Run the code supplied in the description

[1 Dec 2007 5:24] David Cantin

Finally, the bug was probably on the mono side.

I re-run my test case against the pre-release of mono-1.2.6 for Windows and the leak do not append any more.

I took the preview version from there : http://mono.ximian.com/monobuild/preview/download-preview/

[3 Dec 2007 8:08] Tonci Grgin

David, thanks for info provided and your interest in MySQL.