We break down the database to a single table for each area code. When we run a check, we grab the area code for each number and check in the appropriate table, or we grab a group of numbers sharing an area code and check them all at once. This keeps each table down to a reasonable size and speeds the checking process dramatically.
Oh: And NONE of this data is stored in the same database as the Vicidial database (which is ordinarily named "asterisk"). It is in a completely different database, perhaps even on a different server ... but that can cause issues when attempting multiple lead checks as two databases on different servers will not communicate as quickly as two databases on the same server.
We install the system for $300 for those who request it, which includes an update to the version of Vicidial in use by that client.
At present the system will accept single area code files or state files. We have not yet built an importer for "all at once" (the Big File). Of course, this is all designed to import the NDNC files downloaded from donotcall.gov (without alteration, just download the file from the Fed and upload it into the Vicidial NDNC menu added to your box ... and the rest is automated).
We can also obviously add custom import routines for other purposes, and we have for a couple clients but those are for single-shot uses based on a data format that nobody else uses and not helpful for General Public at all.