.Columns() to avoid the noticible performance impact of query, which is also mentioned in the Documentation
"Using Columns method you can restrict the amount of data loaded from the database and speed up the querying process."
Then my question becomes: How to query attachment of the TreeNode obtained from the following code, or what is the right columns reference the attachment?
TreeNode quote = DocumentHelper.GetDocuments()
DocumentHelper.GetAttachments(quote, false); with a "Node site not found" exception.