[HBASE-82] row keys should be array of bytes

• Type: Wish
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.2.0
• Assignee: Michael Stack
• Reporter: Jim Kellerman
• Created: 03/Dec/07 08:12
• Updated: 22/Aug/08 21:13
• Resolved: 15/May/08 22:13

Description

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.

Issue Links

• blocks: HBASE-76 Purge servers of Text
• incorporates: HBASE-404 TextSequence does not obey ISA Text semantics
• incorporates: HBASE-522 Where new Text(string) might be used in client side method calls, add an overload that takes strings
• incorporates: HBASE-570 Remove HQL unit test