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From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-7221) RowKey utility class for rowkey construction
Date Tue, 04 Dec 2012 05:51:59 GMT

    [ https://issues.apache.org/jira/browse/HBASE-7221?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13509529#comment-13509529
] 

Lars Hofhansl commented on HBASE-7221:
--------------------------------------

Interface looks good (so does this idea, generally).

But we are now (kind of) prescribing a way in which HBase should do its encoding.
It seems this is best handled by an external library (orderly or lily do this).

Encoding numbers into correctly sorted byte[] is not entirely trivial, neither is separating
variable length parts of the key, different users will have different needs. Are strings UTF8?
what about special sorting for languages?
What about floats? They need to be encoded to sort correctly even considering their exponents
(again there're libraries out there doing this already).

At the same time everybody using HBase is building something like this, so maybe HBase should
ship with a reasonable set of default encodings.
                
> RowKey utility class for rowkey construction
> --------------------------------------------
>
>                 Key: HBASE-7221
>                 URL: https://issues.apache.org/jira/browse/HBASE-7221
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Doug Meil
>            Assignee: Doug Meil
>            Priority: Minor
>         Attachments: HBASE_7221.patch, hbase-common_hbase_7221_2.patch, hbase-common_hbase_7221_v3.patch
>
>
> A common question in the dist-lists is how to construct rowkeys, particularly composite
keys.  Put/Get/Scan specifies byte[] as the rowkey, but it's up to you to sensibly populate
that byte-array, and that's where things tend to go off the rails.
> The intent of this RowKey utility class isn't meant to add functionality into Put/Get/Scan,
but rather make it simpler for folks to construct said arrays.  Example:
> {code}
>    RowKey key = RowKey.create(RowKey.SIZEOF_MD5_HASH + RowKey.SIZEOF_LONG);
>    key.addHash(a);
>    key.add(b);
>    byte bytes[] = key.getBytes();
> {code} 

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