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From Tyler Hobbs <>
Subject Re: LongString
Date Wed, 01 Sep 2010 16:20:29 GMT
Hey Kevin,

It looks to me like they use LongString to sort primarily by the Long, then
secondarily by the String portion of a "LongString".  I believe all you
would need to do to implement this is to add a class to
src/java/org/apache/cassandra/db/marshal .  I would recommend copying
LongType to start, then adjust the compare() and getString() methods.  As
far as using this for column names goes, I don't think there's anything else
to it.  I'm not sure about row keys.

- Tyler

On Wed, Sep 1, 2010 at 5:27 AM, Kevin Irwig <> wrote:

>  Hi,
> I came across this presentation (link below) by Sarkissian (no first name
> given) at Digg about their use of Cassandra. On page 27 he says "Custom
> comparators turn out to be key" and mentions in the next few slides a
> LongString (actually once a LongString the other times a LongSting, but I'm
> assuming that's just a typo). Most of my CFs use some long strings (urls)
> either as rows or column names, and I'm keen to know more about what they
> may have learned. Does anyone know if they contributed this class to back to
> Cassandra or can anyone guess at how long strings might need to be handled
> differently to what the standard string comparator does?
> Thanks in advance,
> Kevin.

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