Re: [PATCH 00/33] Adaptive read-ahead V12

Andrew Morton
2006-05-26T16:26:33Z

Andi Kleen <ak@suse.de> wrote:
>
> Andrew Morton <akpm@osdl.org> writes:
> >
> > These are nice-looking numbers, but one wonders. If optimising readahead
> > makes this much difference to postgresql performance then postgresql should
> > be doing the readahead itself, rather than relying upon the kernel's
> > ability to guess what the application will be doing in the future. Because
> > surely the database can do a better job of that than the kernel.
>
> With that argument we should remove all readahead from the kernel?
> Because it's already trying to guess what the application will do.
>
> I suspect it's better to have good readahead code in the kernel
> than in a zillion application.
>

Wu: "this readahead patch speeds up postgres"

Me: "but postgres could be sped up even more via X"

everyone: "ah, you're saying that's a reason for not altering readahead!".

Would everyone *please* stop being so completely and utterly thick?

Thank you.