pbxt-discuss team mailing list archive

[erkan yanar <erkan.yanar@xxxxxxxxxxxxx>]

Moin Mark,

reading your post I actively ignored the tmpfs-thing, sorry.
The general question about the way PBXT uses file-system-cache still
stays (for me).


erkan


btw: It "hard" to comment if not in facebook:)

On Fri, Mar 19, 2010 at 10:17:00AM -0700, MARK CALLAGHAN wrote:
> I don't think so. I think all engines were dependent to a similar
> degree on tmpfs and nothing go to use the OS buffer cache.
> 
> AFAIK, tmpfs files are not doubled-buffered in the OS buffer cache. I
> think I learned this from reading lkml, but I don't mind citations
> that state otherwise.
> 
> So, each fetch of a MyISAM row must get all columns and read from the
> file after doing the primary key index lookup that is likely to hit in
> the key cache.
> 
> InnoDB is should do reads from tmpfs for most queries as the table
> data doesn't fit in the InnoDB buffer cache.
> 
> I only set two of the my.cnf settings for PBXT and don't know if that
> was sufficient to keep it from caching too much.
> 
> On Fri, Mar 19, 2010 at 9:13 AM, erkan yanar <erkan.yanar@xxxxxxxxxxxxx> wrote:
> >
> > Moin,
> >
> > I enjoy it seeing PBXT gaining more publicity \o/
> > (http://www.facebook.com/note.php?note_id=378043115932)
> >
> > I wonder if PBXT benefits as much as MyISAM from filesystemcache?
> > Reading the post I think MyISAM is better configured on that machine
> > than InnoDB, because MyISAM benefits a lot from the filesystemcache.
> > And now I wonder about best practice for PBXT.
> >
> >
> > regards
> > erkan
> >
> >
> >
> >
> > --
> > über den grenzen muß die freiheit wohl wolkenlos sein
> >
> > _______________________________________________
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> >
> 
> 
> 
> -- 
> Mark Callaghan
> mdcallag@xxxxxxxxx

-- 
über den grenzen muß die freiheit wohl wolkenlos sein