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From aaron morton <aa...@thelastpickle.com>
Subject Re: Deleting old items during compaction (WAS: Deleting old items)
Date Mon, 18 Feb 2013 20:11:56 GMT
Sorry, missed the Counters part.

You are probably interested in this one 
https://issues.apache.org/jira/browse/CASSANDRA-5228

Add your need to ticket to help it along. IMHO if you have write once, read many time series
data the SSTables are effectively doing horizontal partitioning for you. So been able to "drop
a partition" would make life easier. 

If you can delete entire row then the deletes have less impact than per column. However the
old rows will not be purged from disk unless all fragments of the row are involved in a compaction
process. So it may take some time to purge from disk, depending on the workload. 

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

@aaronmorton
http://www.thelastpickle.com

On 18/02/2013, at 10:43 AM, Ilya Grebnov <ilya@metricshub.com> wrote:

> According to https://issues.apache.org/jira/browse/CASSANDRA-2103 There is no support
for time to live (TTL) on counter columns. Did I miss something?
>  
> Thanks,
> Ilya
> From: aaron morton [mailto:aaron@thelastpickle.com] 
> Sent: Sunday, February 17, 2013 9:16 AM
> To: user@cassandra.apache.org
> Subject: Re: Deleting old items during compaction (WAS: Deleting old items)
>  
> 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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