Update all records in a module

Update all records in a module

I'm trying to create a custom function that would allow me to copy one field to another for all my records (~5,000).  Mass Update is limited to 100 records, so that's not really an option.  The same thing is true for Sheet View.  So far I have come up with this:

list = zoho.crm.getRecords("Contacts");
for each item in list
{
id=item.get("CONTACTID");
resp = zoho.crm.updateRecord("Contacts",id,{ input.newField : item.get(input.oldField) });
}

However, getRecords() is limited to 200 records (and 20 being the default).

Any ideas on how to do this properly?

Thanks

Oliver