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From Mike Malone <m...@simplegeo.com>
Subject Re: pagination through slices with deleted keys
Date Thu, 06 May 2010 21:56:41 GMT
Our solution at SimpleGeo has been to hack Cassandra to (optionally, at
least) be sensible and drop Rows that don't have any Columns. The claim from
the FAQ that "Cassandra would have to check if there are any other columns
in the row" is inaccurate. The common case for us at least is that we're
only interested in Rows that have Columns matching our predicate. So if
there aren't any, we just don't return that row. No need to check if the
entire row is deleted.

Mike

On Thu, May 6, 2010 at 9:17 AM, 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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