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HBase >> mail # dev >> Some suggestions for future features


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Vladimir Rodionov 2012-06-05, 18:19
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Andrew Purtell 2012-06-06, 07:59
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Vladimir Rodionov 2012-06-06, 17:59
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Daniel Iancu 2012-06-08, 16:47
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Anoop Sam John 2012-07-04, 07:04
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Andrew Purtell 2012-06-06, 07:53
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Anoop Sam John 2012-06-06, 08:08
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Andrew Purtell 2012-06-06, 08:42
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Vladimir Rodionov 2012-06-05, 18:44
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Stack 2012-06-05, 18:43
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Vladimir Rodionov 2012-06-05, 19:00
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RE: Some suggestions for future features
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 [[EMAIL PROTECTED]]
Sent: Wednesday, June 06, 2012 12:30 AM
To: [EMAIL PROTECTED]
Subject: RE: Some suggestions for future features

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.

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 purpose.
Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: [EMAIL PROTECTED]

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From: [EMAIL PROTECTED] [[EMAIL PROTECTED]] On Behalf Of Stack [[EMAIL PROTECTED]]
Sent: Tuesday, June 05, 2012 11:43 AM
To: [EMAIL PROTECTED]
Subject: Re: Some suggestions for future features

On Tue, Jun 5, 2012 at 11:19 AM, Vladimir Rodionov
<[EMAIL PROTECTED]> 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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Ian Varley 2012-06-05, 19:34
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Vladimir Rodionov 2012-06-05, 20:32
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Anoop Sam John 2012-06-06, 03:42
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lars hofhansl 2012-06-06, 09:11
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Anoop Sam John 2012-06-06, 10:02