I'm building a fairly complex form in InfoPath 2013 and SharePoint 2010. There is a cascading drop-down where the user selects a province (I'm in Canada), and that selection filters a list of 7000 cities and populates the second drop-down with the cities from that province.
The list of cities is stored in a SharePoint list. The first dd has a rule that sets the province query field on the secondary data connection to the selected province and then queries the data source. The second dd is set to populate from that filtered data source.
First I built this in a separate InfoPath file to make sure it worked, then I re-built it within the big form. When I published the test file, the query and population happened instantly when the province was selected. When I added the same fields, rules and data connections to the big form and published to the same test server, the query take 3-5 minutes to run. It shows the "Sending data to the server" notification, and eventually finishes successfully.
The big form has various other data connections but only one significant one has been called prior to this one.
Any ideas what would cause the same query on the same data source from the same server to perform so vastly different? Are there things I should look for in my main form that might cause such lag?