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From Vladimir Rodionov <vrodio...@carrieriq.com>
Subject RE: Some suggestions for future features
Date Tue, 05 Jun 2012 19:00:34 GMT
My bad, getting through all HBase API is not easy task. I will look at Coprocessor. more closely

Custom Key comparator allows to perform some useful tricks such as:

keeping rows in a chronological order (temporal locality) and allowing to access them by some
rowid at the same time.


We preserve temporal locality for rows and access to the rows by ID at the same time

Although, HBase does not support Get by row prefix API call we can use Scanner for that purpose.

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com

From: saint.ack@gmail.com [saint.ack@gmail.com] On Behalf Of Stack [stack@duboce.net]
Sent: Tuesday, June 05, 2012 11:43 AM
To: dev@hbase.apache.org
Subject: Re: Some suggestions for future features

On Tue, Jun 5, 2012 at 11:19 AM, Vladimir Rodionov
<vrodionov@carrieriq.com> wrote:
> 1. Custom Key, KeyValue, Row Comparators (per HTable). I went through the 0.92 API and
it seems that adding this feature is going to be hard task. There are a lot of places all
over HBase source code
> where KeyValue static class members are accessed directly.

Yes.  Its our most fundamental class.  Its tough to change since it
there are a bunch of perf. fixes and a bunch of the upper tiers key
off its format (and as you note, make direct calls against this

That said, there is pressure building that KV should be an Interface
only because others want to mess w/ its implementation (improve our
cachability, compression).

What would you like to do Vladimir?  You want to change comparators?

> 2.Compaction callback. Can be HTable as well. Something like this one:
> public interface CompactionCallback<KeyValue>
> {
>     public void preCompact(KeyValue kv, CompactionContext ctx)
> }

Is this not in Coproccessors now?  See trunk.  See Compactor.java down
around #136 where the scanner used compacting is overrideable.


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