To fix the problem with database locks during reporting we had to move the creation of the temporary tables used into their own transaction. Unfortunately the Jet database does not recover the disk space when these table are deleted, therefore the database size grows. To shring the database you must dump and load. NOTE: Do not do this while the poster is posting any jobs.
As for performance, it is not the size of the database that matters so much as the number of counters. Therefore if you have a large number of machines with few ballots cast but many for many precincts the counters will get large. This is becoming a bigger issue now that we have more jurisidictions that are doing Early voting and it is one of the many things we have on our plate to try to improve.