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

Con Kolivas
2006-05-27T00:01:04Z

On Saturday 27 May 2006 09:54, Folkert van Heusden wrote:
> > > 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.
>
> Maybe a pluggable read-ahead system could be implemented.

Pluggable anything is unpopular with Linus and other maintainers. See
pluggable cpu scheduler and pluggable page replacement policy (vm) patchsets.

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-ck