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From Vladimir Rodionov <vrodio...@carrieriq.com>
Subject RE: Some suggestions for future features
Date Tue, 05 Jun 2012 20:32:16 GMT
This probably can not be done atomically w/o significant resource investments (time)

I am thinking about using special coprocessor for the vary same purpose. The only requirement
I see right now
is custom compaction support, but Stack said that it is there already.

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

From: Ian Varley [ivarley@salesforce.com]
Sent: Tuesday, June 05, 2012 12:34 PM
To: dev@hbase.apache.org
Subject: Re: Some suggestions for future features

Are you guys thinking this would be a "helper" class that just iterates over rows and marks
them as deleted? Or any attempt to make it a more fundamental atomic delete operation that
can run for rows co-located on a single region server? If the latter, my understanding of
the prevailing opinion (of Todd, etc) is that we're wary of exposing the region concept explicitly
in the API at all, because it's an implementation detail today.


On Jun 5, 2012, at 2:15 PM, Anoop Sam John wrote:

> Hi,
>> 3. Row prefix delete operation - Delete all rows which starts with a 'prefix'
> Sometime back I was thinking about this. One usage came for us.[Which was low prioritized
later ] I will try to work on this soon.
> -Anoop-
> ________________________________________
> From: Vladimir Rodionov [vrodionov@carrieriq.com]
> Sent: Wednesday, June 06, 2012 12:30 AM
> To: dev@hbase.apache.org
> Subject: RE: Some suggestions for future features
> My bad, getting through all HBase API is not easy task. I will look at Coprocessor. more
> 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.
> id1:day1
> id2:day1
> id3:day2
> id4:day2
> id5:day2
> etc
> 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
> 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
> class).
> 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.
> St.Ack
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