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HBase, mail # dev - Some suggestions for future features


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RE: Some suggestions for future features
Anoop Sam John 2012-06-06, 08:08
>This is possible now with the coprocessor RegionObserver API.

Agree with Andrew.  We can make use of the RegionObserver#preCompact() hook here I think. This allows to return an InternalScanner implementation. May be we can wrap the actual InternalScanner object.  This wrapper can do the modifications on the KVs.  Mean while Andrew I have just seen that in trunk the interface InternalScanner is marked as private [@InterfaceAudience.Private]  
Through the CP it is exposed now right. And the above use case need customer to implement this also.  What about marking this Public?  Correct me if my understanding is wrong pls...
Similar discussion is underway in HBASE-5974 regarding marking RegionScanner as Public.

-Anoop-
________________________________________
From: Andrew Purtell [[EMAIL PROTECTED]]
Sent: Wednesday, June 06, 2012 1:23 PM
To: [EMAIL PROTECTED]
Subject: Re: Some suggestions for future features

For this one...

On Tue, Jun 5, 2012 at 8:19 PM, Vladimir Rodionov
<[EMAIL PROTECTED]> wrote:
> 2.Compaction callback. Can be HTable as well. Something like this one:
>
> public interface CompactionCallback<KeyValue>
> {
>     public void preCompact(KeyValue kv, CompactionContext ctx)
> }
>
> Developer can :
> a. Modify KeyValue before compaction
> or
> b. Make HBase to delete row entirely

This is possible now with the coprocessor RegionObserver API.

What is the motivation here for adding another API?

Best regards,

   - Andy

Problems worthy of attack prove their worth by hitting back. - Piet
Hein (via Tom White)