Heikki Linnakangas wrote:
> Russell Smith wrote:
> > 2. Index cleanup is the most expensive part of vacuum. So doing a
> > partial vacuum actually means more I/O as you have to do index cleanup
> > more often.
>
> I don't think that's usually the case. Index(es) are typically only a
> fraction of the size of the table, and since 8.2 we do index vacuums in
> a single scan in physical order. In fact, in many applications the index
> is be mostly cached and the index scan doesn't generate any I/O at all.
Are _all_ the indexes cached? I would doubt that. Also, for typical
table, what percentage is the size of all indexes combined?
--
Bruce Momjian bruce@momjian.us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
