And potentially to tune down the number kept by modifying the appropriate freeze parameter for 8.1 (I'm not sure of the details), so that it keeps perhaps 20MB or so rather than 50MB.
> The expected behavior (in 8.2 and newer) is to maintain about > autovacuum_freeze_max_age transactions' worth of clog; which is to say > about 50MB at the default settings.
The active database I checked, where it didn't go all the way back to 0000, had 50 MB of files; so I guess it is working as intended.
It sounds like the advice to the OP that running VACUUM FREEZE on all databases to clean up the files was off base?