Default autovacuum settings too conservative

As I recall, the idea behind vacuum_threshold was to prevent
too-frequent vacuuming of small tables. I'm beginning to question this
reasoning:

Small tables vacuum very, very quickly, so 'extra' vacuuming is very
unlikely to hurt system performance.

Small tables are most likely to have either very few updates (ie: a
'lookup table') or very frequent updates (ie: a table implementing a
queue). In the former, even with vacuum_threshold = 0 vacuum will be a
very rare occurance. In the later case, a high threshold is likely to
cause a large amount of un-nececcasry bloat.

Also, vacuum_scale_factor of 0.4 seems unreasonably large. It means
tables will be 40% dead space, which seems excessively wasteful.
Something between 0.1 and 0.2 seems much better.

Has anyone looked at how effective these two settings are?
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461