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https://issues.apache.org/jira/browse/HBASE-82?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12570082#action_12570082
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Kevin Beyer commented on HBASE-82:
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Yes, bytes + comparator would work fine for jaql. Preferably, it would be the
same comparators that are already used by the sort code, which work on
serialized bytes (but also on WritableComparables, so that might be a problem).
If these comparators are inconsistent, then the sort in map/reduce will not
work properly. I think it is ok to document the transitivity requirement, but
I don't see how you can enforce it in any way. Different key types are fine,
as long as the comparator knows how to handle them. If you can't reuse the
same comparator interface, I can always implement my comparisons in another
place, but I already have two of them (one in the WritableComparable, and one
in the Comparator).
I don't see how column families and the key comparator are related, except that
they are both table-level metadata. Yes, I agree that a single comparator would
be used for the entire table.
> [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
>
> 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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