Problems with more then 5 CE devices connecting to a webservice

Problems with more then 5 CE devices connecting to a webservice

• prasad_8104

  flandersit wrote:

  the server is heavily loaded because the webservice uses an access database which is not very kind with server load. But still i don't understand why extra connections are opened and how to solve it. You are talking about async service call, normally the webservice is called synchronically. Are am i wrong

  ok, re-reading your other post, sorry, I thought you'd said you had one screen that was open, and another call was then made to the web service, my misunderstanding.

  if more than one connection is being spawned per device, it sounds as if something's being done asynchronously -- which would make sense if your service takes a while to respond.

  a single request should generate a single connection. what resource(s) is/are being requested by each of the connections you should be able to see this in the server logs or monitor.

  
  

• danni123

  to make the problem a little bit more clear, i send you the code used in the program

  Dim dt As wsHaweka.dsKlant.KlantDataTable

  dt = clsAlg.ws.GetKlantInfo(f.txtTva.Text, f.txtTel.Text, f.TxtName.Text, f.txtNr.Text, f.txtZipcode.Text)

  Dim g As New frmLijstKlanten(dt)

  g.ShowDialog()

  g.Dispose()

  we have this problem in frmLijstKlanten. dt is a dataTable.

  clsAlg.ws is the webservice (shared variable)

  So we have only one connection.

  
  

• yvz

  we don't get any error only if more then 10 connections are open. No potential deadlock.

  This is the code in the webservice

  Dim ta_klant As New dsKlantTableAdapters.TA_Klant

  Try

  Return ta_klant.GetKlantInfo(tva, tel, name, customerno, zipcode)

  Catch ex As Exception

  Return Nothing

  Finally

  ta_klant.Dispose()

  End Try

  we only dispose the ws when we exit the program. the webservice is user driven.

  
  

• aguess

  flandersit wrote:

  Strange thing is when we do this with one device we don't get an extra connection. Any idea

  what's the load look like on the server could it simply be serving a single device much faster than multiple devices, so your async service call is served, resolved, and disposed of much more quickly

  
  

• mtm81

  flandersit wrote:

  to make the problem a little bit more clear, i send you the code used in the program Dim dt As wsHaweka.dsKlant.KlantDataTable dt = clsAlg.ws.GetKlantInfo(f.txtTva.Text, f.txtTel.Text, f.TxtName.Text, f.txtNr.Text, f.txtZipcode.Text) Dim g As New frmLijstKlanten(dt) g.ShowDialog() g.Dispose() we have this problem in frmLijstKlanten. dt is a dataTable. clsAlg.ws is the webservice (shared variable) So we have only one connection.

  are all requests being completed on the server any potential deadlock issues any errors/exceptions being recorded

  is clsAlg/clsAlg.ws being disposed of at some point on what basis does the request to the web service occur timed event based user driven

  
  

• Jeroen ter Heerdt

  at server side it uses windows XP professional, with IIS. The webservice connects to an Access 2003 database. With 3 devices it seems always to work, but with more it starts giving errors. With more then 8 it give immediately errors.
  

• ottogbg

  Is there a way to see how many connections are open
  

• enric vives

  flandersit wrote:

  Yes this was the error. What are the limits on IIS. Can they be made bigger. Because it is very strange, we only open one connection or is it possible some connections stay open, how to close them

  http://www.iisanswers.com/IIS51.htm

  XP Pro has a limit of 10 connections to IIS 5.1. I don't believe you can up the limit, MS wants you to buy 2003 server, which offers you the option to alter the number of allowed connections.

  Also, keep in mind, a "connection" doesn't represent a single device necessarily -- one device could make multiple requests, requiring multiple connections to the server at any one time. You could, in theory, use all 10 available connections with a single device.

  
  

• Amjath

  Yes this was the error. What are the limits on IIS. Can they be made bigger. Because it is very strange, we only open one connection or is it possible some connections stay open, how to close them
  

• David Mc Dermid

  There's "Web Service" object in performance monitor which would show this (and much more) information in real time.

  
  
  

• ikarkaroff

  Which error Print it out and see if it's “403.9 Access Forbidden: Too many users are connected Internet Information Services”. If it is, you hit limit on connections. Also I'm not sure about Access, might have a limit as well. I would suggest looking through event log on a server, perhaps it has some information about why connection was refused.

  
  
  

• JJOSHI

  thanks for the helpfull information. Now we can check the number of connections. Here we see the problem. We get more then 10 connections but this only happens if we ask with 8 devices the same webservice. At that moment we see extra connections are opened. As long the screen is open the connections are kept open, when we close that screen that called the webservice the connection closes. But most of the time one or two connections stays open. THis means, we have 8 devices=8 connections, we call a certain screen that calls a webservice which takes quite long to execute, then we get 16 connections for the time that screen is open, we closes the screen we get 9 connections.

  Strange thing is when we do this with one device we don't get an extra connection. Any idea

  
  

• Raba Shani

  the server is heavily loaded because the webservice uses an access database which is not very kind with server load. But still i don't understand why extra connections are opened and how to solve it. You are talking about async service call, normally the webservice is called synchronically. Are am i wrong
  

• Becky N

  I would be looking into the server side, e.g. limits on connections, licenses and so on.

  
  
  
• Problems with more then 5 CE devices connecting to a webservice