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From aaron morton <aa...@thelastpickle.com>
Subject Re: Deleting old items during compaction (WAS: Deleting old items)
Date Sun, 17 Feb 2013 17:16:19 GMT
That's what the TTL does. 

Manually delete all the older data now, then start using TTL. 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 13/02/2013, at 11:08 PM, Ilya Grebnov <ilya@metricshub.com> wrote:

> Hi,
>  
> We looking for solution for same problem. We have a wide column family with counters
and we want to delete old data like 1 months old. One of potential ideas was to implement
hook in compaction code and drop column which we don’t need. Is this a viable option?
>  
> Thanks,
> Ilya
> From: aaron morton [mailto:aaron@thelastpickle.com] 
> Sent: Tuesday, February 12, 2013 9:01 AM
> To: user@cassandra.apache.org
> Subject: Re: Deleting old items
>  
> So is it possible to delete all the data inserted in some CF between 2 dates or data
older than 1 month ?
> No. 
>  
> You need to issue row level deletes. If you don't know the row key you'll need to do
range scans to locate them. 
>  
> If you are deleting parts of wide rows consider reducing the min_compaction_level_threshold
on the CF to 2
>  
> Cheers
>  
>  
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> New Zealand
>  
> @aaronmorton
> http://www.thelastpickle.com
>  
> On 12/02/2013, at 4:21 AM, Alain RODRIGUEZ <arodrime@gmail.com> wrote:
> 
> 
> Hi,
>  
> I would like to know if there is a way to delete old/unused data easily ?
>  
> I know about TTL but there are 2 limitations of TTL:
>  
> - AFAIK, there is no TTL on counter columns
> - TTL need to be defined at write time, so it's too late for data already inserted.
>  
> I also could use a standard "delete" but it seems inappropriate for such a massive.
>  
> In some cases, I don't know the row key and would like to delete all the rows starting
by, let's say, "1050#..." 
>  
> Even better, I understood that columns are always inserted in C* with (name, value, timestamp).
So is it possible to delete all the data inserted in some CF between 2 dates or data older
than 1 month ?
>  
> Alain
>  


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