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From Alfonso Nishikawa <alfonso.nishik...@gmail.com>
Subject Re: Working with arrays in HBase. Do they only grow?
Date Mon, 27 Oct 2014 20:02:40 GMT
Hi, Renato,

I will open a jira to comment there :)
Thanks!

Regards,
Alfonso



2014-10-27 20:38 GMT+01:00 Renato MarroquĂ­n Mogrovejo <
renatoj.marroquin@gmail.com>:

> Hi Alfonso,
>
> You are right, the array can not be shrinked at the moment and yes, it is
> wrong having to write the whole array back if you just want to change a
> single element.
> The column qualifier used for each item is the original index that means if
> your original array had 10 elements, then you'd have 10 column qualfiers to
> store those 10 items. But if then you delete the third element, Gora will
> end up with 9 actual elements (without the third), but there will be a 10th
> element inside HBase :( and when modifying a specific element, we will end
> up rewriting all of the elements :(
> Maybe we should do the same thing, we do with the maps and rewrite them all
> into HBase. At least it will work correctly. Could you open a JIRA for
> that?
> Thanks for pointing this out!
>
>
> Renato M.
>
> 2014-10-27 16:47 GMT+01:00 Alfonso Nishikawa <alfonso.nishikawa@gmail.com
> >:
>
> > Hi, Talat.
> >
> > Thank you for your response.
> >
> > I lost that detail. Never knew that in order to shrink an array we had to
> > nullify first.
> >
> > I don't know how to do in the Pig connector when updating an array... :S
> >
> > So, let me see if I understood. In order to delete an element (shrink) an
> > array you have to:
> >
> > 1 - Define the array as nullable ['null', ...]
> > 2 - Set the array as null in the persistent's field and persist.
> > 3 - Set the new array in the persistent's field and persist.
> >
> > Although it works, I don't know what/why but I find something inherent
> > wrong.
> >
> > Well, at least it is a solution and I can't think about a better way at
> > this moment. Thank you very much :)
> >
> > Regards,
> >
> > Alfonso
> >
> >
> > 2014-10-27 16:28 GMT+01:00 Talat Uyarer <talat@uyarer.com>:
> >
> > > Hi Alfonso,
> > >
> > > As i know when you want to change  array's item you should replace with
> > > null. An then you should set array again. We write over it.
> > >
> > > Talat
> > >  On Oct 27, 2014 4:25 PM, "Alfonso Nishikawa" <
> > alfonso.nishikawa@gmail.com
> > > >
> > > wrote:
> > >
> > > > Hi!
> > > >
> > > > I am working with arrays serialized in HBase and I suspect that when
> > > > persisting arrays to HBase, you can't delete elements (
> > > >
> > > >
> > >
> >
> https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/store/HBaseStore.java#L312
> > > > ).
> > > > The array can only grow.
> > > > Am I missing something or am I right?
> > > >
> > > > Thanks!
> > > >
> > > > Regards,
> > > >
> > > > Alfonso
> > > >
> > >
> >
>

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