WebQueryOpen or not WebQueryOpen?

Especially Jake Howlett is very enthousiastic about WebQueryOpen agents. I agree they offer a lot of unique solutions for difficult problems. But are they fast enough? Let's find out.

The test

I have my WebQueryOpen-free homepage. It is built with an embedded view for the most recent posts. For the side blocks, I use @DbLookups. A few reloads in FireBug gives me load times between 15ms and 31ms, for the HTML only. Note that I live in Belgium, and the server is on the same backbone, so the HTTP request does not have to swim across oceans.

Then I made a WebQueryOpen to replace the embedded view with its LotusScript equivalent. I used the same techniques as in a previous post. I collect the HTML entries in a stringbuffer class and put all of it in a text field at the end of my agent. I also have the HTML for each entry prepared in a computed field, so I can take it right out of the ViewEntry:

Sub Initialize
    
    On Error Goto catch
    Dim ns As New NotesSession
    Dim doc As NotesDocument
    Dim db As NotesDatabase
    Dim view As notesView
    Dim vc As NotesViewEntryCollection
    Dim entry As NotesViewEntry
    
    Dim out As New StringBuffer(100)
    Dim debug As New StringBuffer(100)
    Dim i As Long
    
    Set doc=ns.DocumentContext
    debug.add "Agent started."
    
    DbPath=doc.GetItemValue("DbPath")(0)
    debug.add "DbPath: " + DbPath
    
    Set db=ns.CurrentDatabase
    Set view=db.GetView("vLaunch")
    Set vc = view.AllEntries
    
    out.add "<h1>Homepage - Most recent posts</h1>"
    out.add |<div id="viewbody">|
    For i=1 To 7
        Set entry=vc.GetNthEntry(i)    
        If Not entry Is Nothing Then
            out.add entry.ColumnValues(1)
        End If
    Next
    
    out.add("</div>")
    Goto finally
catch:
    debug.add "Error " & Err & " in line " & Erl & ": " & Error$
    out.add "Error " & Err & " in line " & Erl & ": " & Error$
    Resume finally
finally:
    debug.add "<br />Agent finished."
    doc.replaceitemvalue "HtmlBody", out.collapse("")
    'doc.replaceitemvalue "DebugOut", debug.collapse("<br />")
End Sub

The result

You can test the page with the WebQueryOpen. Surprisingly, I get exactly the same load times as the page with the embedded view: between 15ms and 31ms. There is no trace whatsoever of any delay caused by the agent.

Although my test is but an indication and no real scientific proof, I think we can safely start using WebQueryOpen agents, providing we optimize the agents themselves for performance. It is clear that you don't want to do lots of time-consuming processing in there. I found a good reading start on performance tips on www.nsftools.com.

The next test will be more daring: what would the impact be if I render the complete HTML page from the WebQueryOpen agent?