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From Jun Rao <jun...@almaden.ibm.com>
Subject Re: read repairs for get_columns_since
Date Tue, 21 Apr 2009 21:28:54 GMT

The difference is that for get_slice/get_columns_since, their results are
affected by every update. For get_column, the result only changes when the
asked for column is updated.

Jun
IBM Almaden Research Center
K55/B1, 650 Harry Road, San Jose, CA  95120-6099

junrao@almaden.ibm.com


Jonathan Ellis <jbellis@gmail.com> wrote on 04/20/2009 01:35:34 PM:

>
> It seems to me that you could come up with workloads that would cause
> similar behavior for get_slice as well, or even get_column.  No?
>
> In my mind it would be reasonable to add a read_repair boolean flag to
> all the read API calls.  (But I'm not volunteering to implement that,
> since I don't think we're going to need it in the near future. :)
>
> -Jonathan
>
> On Mon, Apr 20, 2009 at 1:54 PM, Jun Rao <junrao@almaden.ibm.com> wrote:
> >
> > I am wondering is we should really be doing read repairs for
> > get_columns_since. If there is continuous ongoing updates, it's very
likely
> > that two consecutive get_columns_since calls will never return the same
> > result, even when there is no real data loss. It seems that read repair
for
> > this function could add a lot of unnecessary overheads.
> >
> > Jun
> > IBM Almaden Research Center
> > K55/B1, 650 Harry Road, San Jose, CA  95120-6099
> >
> > junrao@almaden.ibm.com
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