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From Franc Carter <franc.car...@sirca.org.au>
Subject Re: Question about 'duplicate' columns
Date Tue, 06 Aug 2013 08:25:32 GMT
On Tue, Aug 6, 2013 at 6:10 PM, Aaron Morton <aaron@thelastpickle.com>wrote:

> Yes. If you overwrite much older data with new data both "versions" of the
> column will remain on disk until compaction get's to work on both fragments
> of the row.
>

thanks


>
> Cheers
>
>  -----------------
> Aaron Morton
> Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
>
> On 6/08/2013, at 6:48 PM, Franc Carter <franc.carter@sirca.org.au> wrote:
>
>
> I've been thinking through some cases that I can see happening at some
> point and thought I'd ask on the list to see if my understanding is correct.
>
> Say a bunch of columns have been loaded 'a long time ago', i.e long enough
> in the past that they have been compacted. My understanding is that if some
> these columns get reloaded then they are likely to sit in additional
> sstables until the larger sstable is called up for compaction, which might
> be a while.
>
> The case that springs to mind is filling small gaps in data by doing bulk
> loads around the gap to make sure that the gap is filled.
>
> Have I understood correctly ?
>
> thanks
>
> --
> *Franc Carter* | Systems architect | Sirca Ltd
>  <marc.zianideferranti@sirca.org.au>
> franc.carter@sirca.org.au | www.sirca.org.au
> Tel: +61 2 8355 2514
>  Level 4, 55 Harrington St, The Rocks NSW 2000
> PO Box H58, Australia Square, Sydney NSW 1215
>
>
>


-- 

*Franc Carter* | Systems architect | Sirca Ltd
 <marc.zianideferranti@sirca.org.au>

franc.carter@sirca.org.au | www.sirca.org.au

Tel: +61 2 8355 2514

Level 4, 55 Harrington St, The Rocks NSW 2000

PO Box H58, Australia Square, Sydney NSW 1215

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