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Memory leak in C# Code

I have a piece of code that going to the database every minute to check if there is any report that need to be run, and if there is any it runs it.
The issue is that my object initiation to a database class creates memory leak. If I look at task mgr "user Object" grown by 5 every time tick executing a code.
private void ReportRunTimer_Tick(object sender, EventArgs e)
{
DataConnection dataConnection = new DataConnection(); *<-- when executing this line User Object increasing.*
try
{
reportsToRun = dataConnection.GetListOfTheReportForReportRunTick();
if (reportsToRun.Count > 0)
foreach (string report in reportsToRun)
{
logs("Starting Automatic report generatin", "Successful");
Thread TicketReportMethodThread = new Thread(() => GenerateReport(report, 1));
TicketReportMethodThread.Start();
}
dataConnection = null;
} catch (Exception ex)
{
logs("Starting Automatic report generatin failed: " +ex.ToString(), "Error");
}
finally
{
reportsToRun.Clear();
}
}
DataConnection class
public List<string> GetListOfTheReportForReportRunTick()
{
List<string> RepoerList = new List<string>();
connString = "Server=xxx;Port=xxx;Database=xxx;Uid=xxx;password=xxxx;SslMode=none";
using (MySqlConnection mySqlConnection = new MySqlConnection(connString))
{
try
{
MySqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.CommandText = "SELECT reportname FROM reports WHERE nextruntime < NOW()";
mySqlConnection.Open();
MySqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader();
while (mySqlDataReader.Read())
{
RepoerList.Add(mySqlDataReader["reportname"].ToString());
}
}
catch (MySqlException ex)
{
hd.logs("Failed to get reports with reportstorun_tick Error: " + ex.ToString(), "Error");
mySqlConnection.Close();
}
finally
{
mySqlConnection.Close();
mySqlConnection.Dispose();
}
}
return RepoerList;
}
DataConnection dataConnection = new DataConnection(); used in a few more places and this is the only one that causing an issue.
If I replace code in private void ReportRunTimer_Tick with code from public List GetListOfTheReportForReportRunTick() like bellow. Issue no longer exist, any ideas?
private void ReportRunTimer_Tick(object sender, EventArgs e)
{
List<string> reportsToRun = new List<string>();
try
{
connString = "Server=xxx;Port=xxx;Database=xxx;Uid=xxx;password=xxxx;SslMode=none";
using (MySqlConnection mySqlConnection = new MySqlConnection(connString))
{
try
{
MySqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.CommandText = "SELECT reportname FROM reports WHERE nextruntime < NOW()";
mySqlConnection.Open();
MySqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader();
while (mySqlDataReader.Read())
{
reportsToRun.Add(mySqlDataReader["reportname"].ToString());
}
if (reportsToRun.Count > 0)
foreach (string report in reportsToRun)
{
logs("Starting Automatic report generatin", "Successful");
Thread TicketReportMethodThread = new Thread(() => GenerateReport(report, 1));
TicketReportMethodThread.Start();
}
}
catch (MySqlException ex)
{
logs("Failed to get reports with reportstorun_tick Error: " + ex.ToString(), "Error");
mySqlConnection.Close();
}
finally
{
mySqlConnection.Close();
mySqlConnection.Dispose();
}
}
}
catch (Exception ex)
{
logs("Starting Automatic report generatin failed: " + ex.ToString(), "Error");
}
finally
{
reportsToRun.Clear();
}
}
Issue is caused by
DataConnection dataConnection = new DataConnection(); *<-- when executing this line User Object increasing.*
reportsToRun = dataConnection.GetListOfTheReportForReportRunTick();
But I can't understand why.

I think the memory leak is because you're not disposing your MySqlDataReader. You can do this by just wrapping it in a using statement like this:
using(MySqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader()){
while (mySqlDataReader.Read())
{
RepoerList.Add(mySqlDataReader["reportname"].ToString());
}
}

Re-try to open a SQL Server connection if failed

I have a C# application which has several methods which connect to a SQL Server database in order to execute a query.
Sometimes the connection fails and then the program exits.
A db administrator is looking on the database nevertheless I have to adapt the program in order to retry 2-3 times when a connection fails before to exiting.
I don't really know who doing this "smartly".
My connection code:
using (SqlConnection SqlCon = new SqlConnection(myParam.SqlConnectionString))
{
SqlCon.Open();
string requeteFou = "select XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
using (SqlCommand command = new SqlCommand(requeteFou, SqlCon))
{
using (SqlDataReader reader = command.ExecuteReader())
{
if (reader.HasRows)
{
while (reader.Read())
{
// do job
}
}
}
}
}
Since I use several methods, is there a simply way to overwrite the "connection" or "read" method in order to retry the connection 3 times for example ?
Best regards

I would use Polly for retry logic.
Very basic example retrying 3 times when there is a SqlException (not tested):
static void Main(string[] args)
{
var policy = Policy
.Handle<SqlException>()
.Retry(3);
try
{
policy.Execute(() => DoSomething());
}
catch (SqlException exc)
{
// log exception
}
}
private static void DoSomething()
{
using (SqlConnection conn = new SqlConnection(""))
{
conn.Open();
string requeteFou = "select XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
using (SqlCommand command = new SqlCommand(requeteFou, conn))
{
using (SqlDataReader reader = command.ExecuteReader())
{
if (!reader.HasRows) return;
while (reader.Read())
{
// do job
}
}
}
}
}

private static function()
{
DataTable dt = new DataTable();
string connectionString = "//your connection string";
String strQuery = //"Yourquery";
const int NumberOfRetries = 3;
var retryCount = NumberOfRetries;
var success = false;
while (!success && retryCount > 0)
{
try
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = conn;
cmd.CommandTimeout = 180;
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
dt.Load(dr);
catch (Exception ex)
{
retryCount--;
Thread.Sleep(1000 * 60 * 15);
if (retryCount == 0)
{
//yourexception
}
}
}
}

Maybe wrap your using in a try block. Log a connection error in a catch block if you want. Put whole try{ }catch{ } in a for loop that will loop 3 times. If try block runs to the end of itself, break out of loop.
for(int i = 0; i < 3; i++)
{
try {
using (SqlConnection SqlCon = new SqlConnection(myParam.SqlConnectionString))
{
// your code
}
Thread.Sleep(1000); // wait some time before retry
break; // connection established, quit the loop
}
catch(Exception e) {
// do nothing or log error
}
}
You'd however have to handle differentiating SQL connection exception from other exceptions that you might encounter in your code.

C# Unable to detach database

I have a class that creates a database that saves the mdf file in a specified location. Then it copies tables from an existing database. Then creates stored procedures from an sql file. Then detaches the database created from the start once the process is done. My problem is that my detach method won't work throwing an exception saying that the database is in use. I have disposed my connections properly.
This is in-line with my previous question.
Here is my class:
Event
private void btnFullBackup_Click(object sender, EventArgs e)
{
progressBar.Value = 0;
lblStatus.Text = "Starting full backup...";
CreateDB("FULL");
progressBar.Value = 20;
lblStatus.Text = "Copying tables...";
CopyTables("FULL");
progressBar.Value = 60;
lblStatus.Text = "Creating stored procedures...";
CreateStoredProcedures("FULL");
progressBar.Value = 70;
progressBar.Value = 80;
DetachBackup("FULL");
lblStatus.Text = "Done";
progressBar.Value = 100;
MessageBox.Show("Backup was created successfully", "",
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
Methods used:
void CreateDB(string type)
{
//define and browse location to save mdf
lblStatus.Text = "Creating pysical database...";
FolderBrowserDialog folderBrowserDialog = new FolderBrowserDialog();
folderBrowserDialog.ShowDialog();
lblStatus.Text = "Checking folder permission...";
string selectedFolder = folderBrowserDialog.SelectedPath + "\\";
newBackupLocation = selectedFolder;
//check permission
if (WriteAccessToFolder(selectedFolder) == false)
{
MessageBox.Show("The folder you have chosen does not have write permission", "Monytron",
MessageBoxButtons.OK, MessageBoxIcon.Error);
folderBrowserDialog.ShowDialog();
return;
}
//create DB
lblStatus.Text = "Creating database...";
string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
var query = GetDbCreationQuery(selectedFolder, type);
using (var conn = new SqlConnection(connectionString))
using (var command = new SqlCommand(query, conn))
{
try
{
conn.Open();
command.ExecuteNonQuery();
folderBrowserDialog.Dispose();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
if ((conn.State == ConnectionState.Open))
{
conn.Close();
}
}
}
}
void CopyTables(string backupDBName)
{
string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
var query = CopyQuery(backupDBName + DateTime.Now.ToString("yyyyMMdd"));
using (var conn = new SqlConnection(connectionString))
using (var command = new SqlCommand(query, conn))
{
try
{
conn.Open();
command.ExecuteNonQuery();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
if ((conn.State == ConnectionState.Open))
{
conn.Close();
}
}
}
}
void CreateStoredProcedures(string type)
{
string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
using (var conn = new SqlConnection(connectionString + ";database=" + type + DateTime.Now.ToString("yyyyMMdd")))
{
string spLocation = File.ReadAllText("CreateStoredProcedures.sql");
Server server = new Server(new ServerConnection(conn));
try
{
server.ConnectionContext.ExecuteNonQuery(spLocation);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
bool DetachBackup(string backupDBName)
{
string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
var builder = new SqlConnectionStringBuilder(connectionString);
string serverName = builder.DataSource;
string dbName = builder.InitialCatalog;
try
{
Server smoServer = new Server(serverName);
smoServer.DetachDatabase(backupDBName + DateTime.Now.ToString("yyyyMMdd"), false);
return true;
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
return false;
}
}

The Connection to the database is in most cases placed in a pool after using. This way you can re-connect quickly using the same connection string, but on the other hand, I suspect this pool of connections is blocking you from detaching a database.
You can probably do something like this:
Put use master as the last statement in each query against database before you close the connection, or
Modify connection string so it doesn't use pooling (uid=...; pwd=...; pooling=false;)
Hope it helps.

You should first kill connections to the database if you want to keep connection pooling. You can do it setting the database in single user access with rollback_immediate clause before calling the detach method.
Have a look here to use C#:
Is there a way to set the DB as Single User Mode in C#?
Or here to run T-SQL script:
https://serverfault.com/questions/76432/how-can-i-detach-a-database-that-is-in-use

Why am I getting this error suddenly Connection Dispose?

The transaction associated with the current connection has completed but has not been disposed. The transaction must be disposed before the connection can be used to execute SQL statements.
protected string installDatabase(string connectionString, bool createSampleData,string scriptpath)
{
//uncomment this line to support transactions
using (var scope = new System.Transactions.TransactionScope())
{
string scriptsFolder = scriptpath + "\\install\\Scripts";
string createDatabaseFile = string.Format(#"{0}\{1}", scriptsFolder, "Campus.sql");
string error = proceedSQLScripts(createDatabaseFile, connectionString);
if (!String.IsNullOrEmpty(error))
{
return error;
}
scope.Complete();
}
return "true";
}
protected string proceedSQLScripts(string pathToScriptFile, string connectionString)
{
List<string> statements = new List<string>();
SqlConnection conn = new SqlConnection(connectionString);
conn.Open();
using (Stream stream = File.OpenRead(pathToScriptFile))
using (StreamReader reader = new StreamReader(stream))
{
string statement = string.Empty;
while ((statement = readNextStatementFromStream(reader)) != null)
{
statements.Add(statement);
}
}
try
{
foreach (string stmt in statements)
{
{
SqlCommand command = new SqlCommand(stmt, conn);
command.ExecuteNonQuery();
//conn.Close();
}
}
}
catch (Exception ex)
{
return ex.Message;
}
finally
{
conn.Close();
}
return string.Empty;
}

Try the following code
Finally
{
conn.Close();
conn.Dispose();
}

How to using oracledataadapter with transaction?

I use a method to gettable using a Select statiments.When i use a select statiment using a link database i got error (ORA-01453 SET TRANSATION must be first statement of transation.)
I know solition but i cant use Transaction methot with Oracledataadapter.
I want to use Commit() ... Rollback().
This is my code:
private System.Data.DataTable GetDataTable_(string SqlStatement, bool fromProcCall)
{
OracleConnection Con = new OracleConnection();
try
{
Con = Connection();
OpenConnection(Con, fromProcCall);
//-----------------------------------------
DateTime startTime = DateTime.Now;
//-----------------------------------------
DataSet ds = new DataSet();
OracleDataAdapter sda = new OracleDataAdapter(SqlStatement, Con);
sda.Fill(ds, "tbl1");
//-----------------------------------------
if (!fromProcCall)
DurationOfIfsAction = DateTime.Now.Subtract(startTime).Milliseconds;
else
DurationOfFirstIfsAction = DateTime.Now.Subtract(startTime).Milliseconds;
//-----------------------------------------
CloseConnection(Con);
return ds.Tables[0];
}
catch (Exception ex)
{
if (Con != null)
{
try
{
CloseConnection(Con);
}
catch (Exception) { }
}
throw new Exception("ERROR[" + ex.Message + "]");
}
}

Basically, you could do something like this:
oraConn = new OracleConnection("CONNECTION STRING");
oraConn.Open();
//Command with transaction
OracleCommand oraCom = oraConn.CreateCommand();
oraCom.CommandText = "INSERT QUERY";
oraCom.Transaction = oraCom.Connection.BeginTransaction(IsolationLevel.ReadCommitted);
//Execute
if (oraCom.Connection.State == ConnectionState.Closed)
{
oraCom.Connection.Open();
}
oraCom.ExecuteNonQuery();
//Commit / Rollback
oraCom.Transaction.Commit(); // or oraCom.Transaction.Rollback();
To use this with DataAdapter, the concept is the same: Create the transaction setting the DataAdapter.SelectCommand.Transaction and then you can control with Commit() and Rollback().