Re: Visibility map, partial vacuums

On Nov 23, 2008, at 3:18 PM, Tom Lane wrote:
> So it seems like we do indeed want to rejigger autovac's rules a bit
> to account for the possibility of wanting to apply vacuum to get
> visibility bits set.

That makes the idea of not writing out hint bit updates unless the
page is already dirty a lot easier to swallow, because now we'd have
a mechanism in place to ensure that they were set in a reasonable
timeframe by autovacuum. That actually wouldn't incur much extra
overhead at all, except in the case of a table that's effectively
write-only. Actually, that's not even true; you still have to
eventually freeze a write-mostly table.
--
Decibel!, aka Jim C. Nasby, Database Architect decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828