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Re: sort: Parallel merging
From: |
Chen Guo |
Subject: |
Re: sort: Parallel merging |
Date: |
Wed, 17 Feb 2010 14:59:32 -0800 (PST) |
BTW, Shaun, this is Glen's patch from a year ago.
Also, forgot to CC the mailing list, so I'm gonna paste my last email:
Hi Shaun
> > As for buffer size, I highly doubt using 8 mb, even if we're magically
> > guaranteed to get 100% of the cpu cache, would work better than a larger
> > buffer.
> >
> > The main reason would be for larger files, you'd have to repeatedly
> > write
> > temporary files out to disk, then merge those temporary files. Whatever
> > time you save talking to cache is more than lost to the extra time talking
> > to disk.
>
> What if the temporary files were stored in RAM (i.e. tmpfs) rather than
> on magnetic disk?
I think I'm misunderstanding what you're trying to say... But the file stored
in ram would be in a buffer. --buffer-size sets the size of this buffer, i.e.
how
much space in RAM you want to allocate to sort.
tt
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