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Date: Fri, 25 Apr 2008 17:09:55 -0700 (PDT)
From: "stack (JIRA)" <jira@apache.org>
To: hbase-dev@hadoop.apache.org
Subject: [jira] Commented: (HBASE-82) row keys should be array of bytes with
 a specified comparator
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    [ https://issues.apache.org/jira/browse/HBASE-82?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12592532#action_12592532 ] 

stack commented on HBASE-82:
----------------------------

I don't think it that basic.  We still need to read in the arguments.  Longest times inside in the 7% are creation of new Writable instance ~2%, doing BatchUpdate readFields ~1%, Text.readString ~1%.  My guess is that hardwiring we could save about 10% -- maybe 20% at the outside.

My takeaway though is that RPC messing requires more study, study to be done outside of this issue I'd say.

> row keys should be array of bytes with a specified comparator
> -------------------------------------------------------------
>
>                 Key: HBASE-82
>                 URL: https://issues.apache.org/jira/browse/HBASE-82
>             Project: Hadoop HBase
>          Issue Type: Wish
>            Reporter: Jim Kellerman
>            Assignee: stack
>             Fix For: 0.2.0
>
>
> I have heard from several people that row keys in HBase should be less restricted than hadoop.io.Text.
> What do you think?
> At the very least, a row key has to be a WritableComparable. This would lead to the most general case being either hadoop.io.BytesWritable or hbase.io.ImmutableBytesWritable. The primary difference between these two classes is that hadoop.io.BytesWritable by default allocates 100 bytes and if you do not pay attention to the length, (BytesWritable.getSize()), converting a String to a BytesWritable and vice versa can become problematic. 
> hbase.io.ImmutableBytesWritable, in contrast only allocates as many bytes as you pass in and then does not allow the size to be changed.
> If we were to change from Text to a non-text key, my preference would be for ImmutableBytesWritable, because it has a fixed size once set, and operations like get, etc do not have to something like System.arrayCopy where you specify the number of bytes to copy.
> Your comments, questions are welcome on this issue. If we receive enough feedback that Text is too restrictive, we are willing to change it, but we need to hear what would be the most useful thing to change it to as well.

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