On Jan 3, 2007, at 11:42 PM, ITAGAKI Takahiro wrote:
> BTW, if we want to achieve the index-only scan, we might have to do
> more
> aggressive VACUUM FREEZE. There were many comments that we should
> avoid
> vacuuming pages that contain only unfrozen tuples or a few dead
> tuples.
> I think it it true for efficient VACUUM, but the index-only scan
> does not
> work for the unfrozen pages. Which should we give priority?
Unless I'm mistaken, as soon as vacuum decides to dirty a page, the
only cost involved in freezing the page is CPU - and vacuum isn't
exactly a CPU-intensive process.
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)