Re: perfromance impact of vacuum

scott.marlowe wrote:
> > The stand-alone analyse can be helpful here.  It only does
> > samples of the tables under analysis, so you don't face the same I/O
> > load.  If all you're doing is adding to a table, it may be worth
> > investigating.  Keep in mind, though, you still need to vacuum every
> > 2 billion transactions.
>
> this sounds like one of those places where the ability of a file system to
> be told not to cache the accesses of a certain child process would be a
> big win.
>
> Wasn't there some discussionon BSD's ability to do this recently and
> whether it was a win to port it into postgresql. I'd say that for large
> databases being vacuumed mid-day it would be a great win.

It was Solaris with free-behind.  I hope new caching rules will fix this
soon --- a few people are working on it.

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