[ 
https://issues.apache.org/jira/browse/HBASE-82?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12569139#action_12569139
 ] 

Bryan Duxbury commented on HBASE-82:
------------------------------------

Specifying a comparator would cause just as much difficulty as making the 
HTables generic in the first place. This is because region servers would have 
to have the comparator code on hand in order to produce proper orderings in 
mapfiles and on gets and puts. Correct me if I'm wrong, but this would also 
require code distribution and restarting of HBase. 

I envisioned HBase as a long-running process, which means that restarting it to 
use a different key or comparator would be somewhat cumbersome. If there's a 
way to distribute new code to servers at runtime, it'd be a different story.

Can you give some examples of complex types that would be used as keys in jaql?

> [hbase] VOTE: should row keys be less restrictive than hadoop.io.Text?
> ----------------------------------------------------------------------
>
>                 Key: HBASE-82
>                 URL: https://issues.apache.org/jira/browse/HBASE-82
>             Project: Hadoop HBase
>          Issue Type: Wish
>            Reporter: Jim Kellerman
>            Priority: Minor
>
> 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.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.

Reply via email to