Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH 00/33] Adaptive read-ahead V12 | Date | Sat, 27 May 2006 10:08:41 +1000 |
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On Saturday 27 May 2006 10:00, Con Kolivas wrote: > 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.
Sorry I should have been clearer. The belief is that certain infrastructure components do not benefit from a pluggable framework, and readeahead probably comes under that description. It's not like Linus was implying we should only have one filesystem for example, since filesystems are afterall pluggable features.
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