I kinda have an idea about how to do this but I wanted to throw it out there in case there's a method I haven't thought of.
In my app, I want to have a FilteringSelect listbox so that users can start typing the name of a road within my county. The dataset of roads has close to 40,000 features so that's obviously way too many records for the FilteringSelect. If I run a frequency based on the street name attribute field, I'm down to 5,000+ unique values.
My thoughts were to create the frequency table on street names, publish that in a service along with setting the returnMaxRecords to just above the maximum number of records in the table, and then setting the FilteringSelect data store to all the records when the app loads. Is that the best way to do this?
The only other thing I can think of is tapping into the keypress event of the FilteringSelect box so that everytime a key is pressed, the street feature service is queried for "like" records (i.e. "NAME like 'Main*'") and update the data store for the FilteringSelect. Something tells me that this won't be that responsive from a user perspective, though.