c22joe c22joe - 2 months ago 28
C# Question

Azure - SqlBulkCopy throwing a timeout expired exception

I'm using an azure sql database (v12) on a vm. I have two different databases instances - one for staging and one for production. I'm trying to grab the data off of staging and insert it into production with the click of a button. This code works successfully 'sometimes' meaning randomly it will be successful. Otherwise I'm getting back an error of:


BULK COPY Commit Exception Type: {0}System.Data.SqlClient.SqlException BULK COPY Message: {0}Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. This failure occurred while attempting to connect to the routing destination. The duration spent while attempting to connect to the original server was - [Pre-Login] initialization=1; handshake=17; [Login] initialization=0; authentication=0; [Post-Login] complete=0;


Here is the code that I'm using to accomplish this task, maybe there's a flaw that I'm not seeing. By dump the StringBuilder out I can see that the SELECT query works and the DELETE query works but the error is thrown when I attempt to copy the data using SqlBulkCopy. Any help would be greatly appreciated. I've gone through a bunch of the MSDN docs already with no luck -> adding longer CommandTimeouts, adding a longer BulkCopyTimeout, and re-configuring ports on my firewall. Still no luck.

Resources I've used: https://social.msdn.microsoft.com/Forums/en-US/1467d64f-69ae-4c1f-91a2-349fc5d514ae/sqlbulkcopy-fails-with-timeout-expired-error?forum=adodotnetdataproviders

https://azure.microsoft.com/nb-no/documentation/articles/sql-database-develop-direct-route-ports-adonet-v12/

Timeout expired with SqlBulkCopy

public static object SyncData()
{
StringBuilder sb = new StringBuilder();
sb.AppendLine("Internal Connection...");
string internalConnectionString = GetConnectionString("ConnectionString");
using (SqlConnection internalConnection = new SqlConnection(internalConnectionString))
{
internalConnection.Open();
SqlCommand selectCommand = internalConnection.CreateCommand();
selectCommand.CommandTimeout = 180;
try
{
selectCommand.CommandText = "SELECT * FROM dbo.test";
SqlDataReader reader = selectCommand.ExecuteReader();

sb.AppendLine("External Connection...");
string externalConnectionString = GetConnectionString("ExternalConnectionString");
using (SqlConnection externalConnection = new SqlConnection(externalConnectionString))
{
externalConnection.Open();
SqlCommand CRUDCommand = externalConnection.CreateCommand();
CRUDCommand.CommandTimeout = 180;
SqlTransaction transaction = externalConnection.BeginTransaction("test");
CRUDCommand.Connection = externalConnection;
CRUDCommand.Transaction = transaction;
try
{
CRUDCommand.CommandText = "DELETE FROM dbo.test";
sb.AppendLine("DELETE: Number of rows affected = " + CRUDCommand.ExecuteNonQuery());
using (SqlBulkCopy bulkCopy = new SqlBulkCopy(externalConnection, SqlBulkCopyOptions.KeepIdentity, transaction))
{
try
{
bulkCopy.DestinationTableName = "dbo.test";
bulkCopy.BatchSize = 100;
bulkCopy.BulkCopyTimeout = 180;
bulkCopy.WriteToServer(reader);

sb.AppendLine("Table data copied successfully");

transaction.Commit();
sb.AppendLine("Transaction committed.");
}
catch (Exception ex)
{
sb.AppendLine("BULK COPY Commit Exception Type: {0}" + ex.GetType());
sb.AppendLine(" BULK COPY Message: {0}" + ex.Message);
try
{
transaction.Rollback();
}
catch (Exception ex2)
{
sb.AppendLine("Rollback Exception Type: {0}" + ex2.GetType());
sb.AppendLine(" Message: {0}" + ex2.Message);
}
}
finally
{
reader.Close();
}
}
}
catch (Exception ex)
{
sb.AppendLine("Commit Exception Type: {0}" + ex.GetType());
sb.AppendLine(" Message: {0}" + ex.Message);

try
{
transaction.Rollback();
}
catch (Exception ex2)
{
sb.AppendLine("Rollback Exception Type: {0}" + ex2.GetType());
sb.AppendLine(" Message: {0}" + ex2.Message);
}
}
}
}
catch (Exception ex)
{
sb.AppendLine("Commit Exception Type: {0}" + ex.GetType());
sb.AppendLine(" Message: {0}" + ex.Message);
}
}
return sb.ToString();
}

Answer

When creating your SqlBulkCopy instance, you're passing the connection string externalConnectionString and thus opening a new connection. That may be causing a deadlock issue with both connections trying to modify the same table.

Have you tried passing your existing connection externalConnection to the SqlBulkCopy constructor instead of the connection string?