Re: Performance question (stripped down the problem)

On Thu, 27 Sep 2001, Steve Wolfe wrote:

>   This is interesting, just yesterday I was perusing some of Bruce
> Momjian's works on PG tuning, and noticed that Postgres prefers sequential
> scans over indexes when much of the table has to be read, all because of
> the number of head movements on the disk.   It would seem that these days,
> where RAM is cheap, that most people have a great enough disk cache that
> head movements can become irrelevant.
>
>   However, I can also see where some people may have incredibly large
> tables that just won't fit into RAM.  An easy solution to both might be to
> create a user-specifiable switch passed at startup that would simply tell
> PG that sequentials aren't necessarily better than index scans.  Not
> completely disabling them, but at least giving it a pointer that it
> doesn't *have* to use sequentials.
The problem is that *both* methods are to slow for my application :-(.

Kind regards

         Andreas.