Possible TODO item? VACUUM on empty table

Over on the support lists we've seen a couple of examples this week of 
people doing a bulk import/delete/replace cycle with a vacuum analyse 
just after the delete.

Instinctively, it's where you'd vacuum and I'm guessing the analyse just 
gets typed at the same time from habit (I know I've done so more than 
once). Of course, it flattens your stats and your import can then take 
forever.

So - would it be worth, in the case of vacuum+analyse (but not analyse 
alone), where the table is completely empty then just halve the existing 
stats.

That way, if you're in the middle of a delete/replace cycle your stats 
will still be in the realms of reasonableness. On the other hand, if the 
table is genuinely empty and you're running a nightly vacuum the stats 
will tend toward 0.

Against the idea:
1. It's a special-case in the code
2. There's a work-around (unless you're running pg_autovacuum I'd guess)
2. We perhaps want a more general table description (this is a 
bulk-loading table, this is a log table, this is a mostly static lookup 
table)

--  Richard Huxton  Archonet Ltd