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From "shweta.agrawal" <shweta.agra...@orkash.com>
Subject Re: how to maintain versioning in D4M schema?
Date Fri, 27 Nov 2015 09:16:33 GMT
Thanks for the answer.
But I am asking about versioning in D4M style. How can I use versioning 
iterator in D4M style as in D4M style, in Rowid id is strored and 
field|value is stored in ColumnQualifier. So as value is stored in 
columnQualifier I cannot maintain versions through versioning iterator. 
So I am asking how will I maintain versioning in D4M style?

Thanks
Shweta

On Friday 27 November 2015 12:45 PM, Dylan Hutchison wrote:
> In order to store five versions of a key but return only one of them 
> during a scan, set the minc and majc VersioningIterator to 5 and set 
> the scan VersioningIterator to 1.  You can set scanning iterators on a 
> per-scan basis if this helps.
>
> It is not necessary to put the timestamp in the column family if you 
> are going with the VersioningIterator approach.
>
> There are many ways to achieve versioning in Accumulo. As the 
> designer/programmer, you must choose one that fits your application, 
> of which we do not know the full details. It sounds like you have 
> narrowed your choice to (1) putting the timestamp in the column 
> family, or (2) not putting the timestamp anywhere else but instead 
> changing the VersioningIterator such that Accumulo stores more 
> versions than the latest version of a (row,colfam,colqual,colvis) key.
>
>
>
> On Thu, Nov 26, 2015 at 8:45 PM, mohit.kaushik 
> <mohit.kaushik@orkash.com <mailto:mohit.kaushik@orkash.com>> wrote:
>
>     David,
>
>     But this is the case when we store versions based on timestamp
>     field. The point is, in D4M schema we can not achieve it by doing
>     this. In this case we are considering CF to store timestamp in
>     reverse order as described by Dylan. Then how can we configure
>     Accumulo to return only latest version and store only 5 versions?
>
>     Thanks
>     Mohit Kaushik
>
>     On 11/27/2015 09:54 AM, David Medinets wrote:
>>      From the user manual:
>>
>>     user@myinstance  mytable>  config  -t  mytable  -s  table.iterator.scan.vers.opt.maxVersions=5
>>     user@myinstance  mytable>  config  -t  mytable  -s  table.iterator.minc.vers.opt.maxVersions=5
>>     user@myinstance  mytable>  config  -t  mytable  -s  table.iterator.majc.vers.opt.maxVersions=5
>>
>>     On Thu, Nov 26, 2015 at 11:10 PM, shweta.agrawal
>>     <shweta.agrawal@orkash.com <mailto:shweta.agrawal@orkash.com>> wrote:
>>
>>         I want to maintain 5 versions only and user can enter any
>>         number of versions but I want to keep only 5 latest version.
>>
>>
>>         On Friday 27 November 2015 09:38 AM, David Medinets wrote:
>>>         Do you want five versions of every entry or will the number
>>>         of versions vary?
>>>
>>>         On Thu, Nov 26, 2015 at 10:53 PM, shweta.agrawal
>>>         <shweta.agrawal@orkash.com
>>>         <mailto:shweta.agrawal@orkash.com>> wrote:
>>>
>>>             Thanks Dylan and David.
>>>             I can store version information in column family. But my
>>>             problem is when I have many versions of the same key how
>>>             will I manage that. In Accumulo versioning I can specify
>>>             that how many versions I want to manage.
>>>
>>>             Suppose I have 10 versions and I only want 5 versions to
>>>             store, how to manage this in a big table?
>>>
>>>             Thanks
>>>             Shweta
>>>
>>>             On Thursday 26 November 2015 10:22 PM, David Medinets wrote:
>>>>             What are the query patterns? If you are versioning for
>>>>             auditing then changing the VersioningIterator seems the
>>>>             easiest approach. You could also store
>>>>             application-specific version information in the column
>>>>             family. One of the reasons that D4M does not use it is
>>>>             to allow application-specific uses. Using the CF means
>>>>             that any applications that understand D4M would not
>>>>             need to change their queries to adjust for the version
>>>>             information.
>>>>
>>>>             On Thu, Nov 26, 2015 at 4:26 AM, shweta.agrawal
>>>>             <shweta.agrawal@orkash.com
>>>>             <mailto:shweta.agrawal@orkash.com>> wrote:
>>>>
>>>>                 Hi,
>>>>
>>>>                 I have my data stored in D4M style. I also want to
>>>>                 maintain versions of different value on the basis
>>>>                 of time.  As in D4M style  data is only in rowid
>>>>                 and colQualifier only.
>>>>
>>>>                 Is there any way to achieve versioning in D4M schema?
>>>>
>>>>                 Thanks
>>>>                 Shweta
>>>>
>>>>
>>>
>>>
>>
>>
>
>
>     -- 
>
>     *Mohit Kaushik*
>     Software Engineer
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