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From David Boxenhorn <da...@lookin2.com>
Subject Re: Multi-tenancy, and authentication and authorization
Date Wed, 19 Jan 2011 09:12:58 GMT
I'm not sure that "you'd still want to retain the ability to individually
control how flushing happens on a per-cf basis in order to cater to
different workloads that benefit from different flushing behavior". It seems
to me like a good system-wide algorithm that works dynamically, and takes
into account moment-by-moment usage, can do this better than a human who is
guessing and making decisions on a static basis.

Having said that, my suggestion doesn't really depend so much on having one
memtable or many. Rather, it depends on making flushing behavior dependent
on system-wide parameters, which reflect the actual physical resources
available per node, rather than per-CF parameters (though per-CF tuning can
be taken into account, it should be a suggestion that gets overridden by
system-wide needs).



On Wed, Jan 19, 2011 at 10:48 AM, Peter Schuller <
peter.schuller@infidyne.com> wrote:

> > Right now there is a one-to-one mapping between memtables and SSTables.
> > Instead of that, would it be possible to have one giant memtable for each
> > Cassandra instance, with partial flushing to SSTs?
>
> I think a complication here is that, although I agree things need to
> be easier to tweak at least for the common case, I'm pretty sure you'd
> still want to retain the ability to individually control how flushing
> happens on a per-cf basis in order to cater to different workloads
> that benefit from different flushing behavior.
>
> I suspect the main concern here may be that there is a desire to have
> better overal control over how flushing happens and when writes start
> blocking, rather than necessarily implying that there can't be more
> than one memtable (the ticket Stu posted seems to address one such
> means of control).
>
> --
> / Peter Schuller
>

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