I have an ASP.NET web application using Entity Framework and a MySQL database. I am doing some work with dynamic tables so have resorted to writing raw SQL. Is there something I need to add to make this code thread-safe? This code can and will be called very frequently for every user of my system. It always the call against INFORMATION_SCHEMA
that errors.
Here is the error I receive fairly often attempting to call AddMessageAction
(but not everytime):
UserActionModel:CheckTableExists ex: The underlying provider failed on Open..
4/23/2013 9:00:24 AM: UserActionModel:CheckTableExists inner ex: System.NotSupportedException: Multiple simultaneous connections or connections with different connection strings inside the same transaction are not currently supported.
at MySql.Data.MySqlClient.ExceptionInterceptor.Throw(Exception exception)
at MySql.Data.MySqlClient.MySqlConnection.Throw(Exception ex)
at MySql.Data.MySqlClient.MySqlConnection.Open()
at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure).
And the code:
public static class UserActionModel
{
private const string databaseName = "chat";
public static string CheckTableExists(long _userId)
{
string tableName = null;
List<long> tableExists;
try
{
string date = DateTime.Now.ToUniversalTime().Year.ToString() + DateTime.Now.ToUniversalTime().Month.ToString("D2") + DateTime.Now.ToUniversalTime().Day.ToString("D2");
tableName = "user_actions_" + date + "_" + _userId;
string sql = "SELECT COUNT(*) FROM information_schema.TABLES WHERE TABLE_NAME = '" + tableName + "' AND TABLE_SCHEMA = 'archive'";
using (var readContext = new ArchiveConnector())
{
tableExists = readContext.Database.SqlQuery<long>(sql).ToList();
readContext.Database.Connection.Close();
}
if (tableExists.Any(tableExist => tableExist == 0))
{
sql = "CREATE TABLE IF NOT EXISTS `" + tableName + "` ("
+ "`id` bigint(20) NOT NULL AUTO_INCREMENT, "
+ "`user_id` bigint(20) NOT NULL, "
+ "`user_device_id` bigint(20) NOT NULL, "
+ "`coordinate_address_id` bigint(20) NOT NULL, "
+ "`message_id` bigint(20) DEFAULT NULL, "
+ "`created` datetime NOT NULL, "
+ "PRIMARY KEY (`id`), "
+ "KEY `user_id` (`user_id`), "
+ "KEY `user_device_id` (`user_device_id`), "
+ "KEY `coordinate_address_id` (`coordinate_address_id`), "
+ "KEY `message_id` (`message_id`); "
using (var writeContext = new ArchiveConnector())
{
writeContext.Database.ExecuteSqlCommand(sql);
writeContext.SaveChanges();
writeContext.Database.Connection.Close();
}
}
}
catch (Exception ex)
{
Logger.LogMessage("UserActionModel:CheckTableExists ex: " + ex.Message);
if (ex.InnerException != null)
Logger.LogMessage("UserActionModel:CheckTableExists inner ex: " + ex.InnerException);
tableName = null;
}
return tableName;
}
public static void AddMessageAction(long _messageId, long _userId, long _userDeviceId, long _coordinateAddressId)
{
try
{
string tableName = CheckTableExists(_userId);
if (String.IsNullOrEmpty(tableName)) return;
using (var dataContext = new ArchiveConnector())
{
string sql = "INSERT INTO " + tableName + " "
+ "(user_id, user_device_id, coordinate_address_id, message_id, created) "
+ "VALUES "
+ "(" + _userId + ", " + _userDeviceId + ", " + _coordinateAddressId + ", " + _messageId + ", NOW());";
dataContext.Database.ExecuteSqlCommand(sql);
dataContext.SaveChanges();
}
}
catch (Exception ex)
{
Logger.LogMessage("UserActionModel:AddMessageAction (" + _messageId + ") ex: " + ex.Message);
}
}
}
Removing persist security info=True
from my web.config connection string made no difference (I read about that being a possible solution).
UDPATE: updated from connector 6.6.4 to 6.6.5. no change. UDPATE: updated from connector 6.6.5 to 6.7.1 Alpha. no change.