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From: Mark Greene <greenemj@gmail.com>
Date: Thu, 6 May 2010 12:26:13 -0400
Message-ID: <j2j41fe9a101005060926t5900c96cx86a37e72cfd20ef1@mail.gmail.com>
Subject: Re: pagination through slices with deleted keys
To: user@cassandra.apache.org
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Hey Ian,

I actually just wrote a quick example of how to iterate over a CF that may
have tombstones. This may help you out:
http://markjgreene.wordpress.com/2010/05/05/iterate-over-entire-cassandra-column-family/

On Thu, May 6, 2010 at 12:17 PM, Ian Kallen <spidaman.list@gmail.com> wrote:

> I read the DistributedDeletes and the range_ghosts FAQ entry on the wiki
> which do a good job describing how difficult deletion is in an eventually
> consistent system. But practical application strategies for dealing with it
> aren't there (that I saw). I'm wondering how folks implement pagination in
> their applications; if you want to render N results in an application, is
> the only solution to over-fetch and filter out the tombstones? Or is there
> something simpler that I overlooked? I'd like to be able to count (even if
> the counts are approximate) and fetch rows with the deleted ones filtered
> out (without waiting for the GCGraceSeconds interval + compaction) but from
> what I see so far, the burden is on the app to deal with the tombstones.
>  -Ian
>

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Hey Ian,<div><br></div><div>I actually just wrote a quick example of how to=
 iterate over a CF that may have tombstones. This may help you out:=A0<a hr=
ef=3D"http://markjgreene.wordpress.com/2010/05/05/iterate-over-entire-cassa=
ndra-column-family/">http://markjgreene.wordpress.com/2010/05/05/iterate-ov=
er-entire-cassandra-column-family/</a><br>

<br><div class=3D"gmail_quote">On Thu, May 6, 2010 at 12:17 PM, Ian Kallen =
<span dir=3D"ltr">&lt;<a href=3D"mailto:spidaman.list@gmail.com">spidaman.l=
ist@gmail.com</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">

I read the DistributedDeletes and the range_ghosts FAQ entry on the wiki wh=
ich do a good job describing how difficult deletion is in an eventually con=
sistent system. But practical application strategies for dealing with it ar=
en&#39;t there (that I saw). I&#39;m wondering how folks implement paginati=
on in their applications; if you want to render N results in an application=
, is the only solution to over-fetch and filter out the tombstones? Or is t=
here something simpler that I overlooked? I&#39;d like to be able to count =
(even if the counts are approximate) and fetch rows with the deleted ones f=
iltered out (without waiting for the GCGraceSeconds interval + compaction) =
but from what I see so far, the burden is on the app to deal with the tombs=
tones.<br>

<font color=3D"#888888">
-Ian<br>
</font></blockquote></div><br></div>

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