Why might a SqlTransaction fail to commit when the commit function is called?

Question

I'm running into an issue where changes made are being rolledback even when none of the queries throw an exception. It's strange since the code works in one environment but isn't committing changes in another.

Here is the function that handles the transaction. When I put a break point on the commit I hit the commit and I can see the changes in the database but when the transaction is disposed the changes are rolled back.

UPDATE:Additional tests show that it isn't a problem with the transaction. If the transaction is completely removed from the code below the app behaves in the same way. The changes are undone when the connection closes.

public bool Transaction(List<string> sqlStatements)
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        conn.Open();
        using (SqlTransaction tran = conn.BeginTransaction())
        {
            try
            {
                foreach (string query in sqlStatements)
                {
                    SqlCommand cmd = new SqlCommand(query, conn, tran);
                    cmd.CommandTimeout = 300;
                    cmd.ExecuteNonQuery();
                }

                tran.Commit();

                return true;
            }
            catch (SqlException sqlError)
            {
                tran.Rollback();
                //Log Exception
                return false;
            }
        }
    }
}

Answer 1

This issue was eventually tracked back to a trigger that had recently been updated to include a transaction.

We solved the issue by removing the transaction from the trigger.