what is the limit of how many people ReadReasources(filterXML, false) can process?

i am using this code to for resource custom fields updates and it looks to me that the code fails if i have over 2,000 resources to process. Can anyone recommend a solution?

   Guid[] resources = EnsureEnterpriseResources(resourceSvc, empNames);

                resourceFilter = GetResourceFilter(resources);

                filterXml = resourceFilter.GetXml();

                resourceDs = resourceSvc.ReadResources(filterXml, false);   //this will be null if too many resources to process

tatiana