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https://issues.apache.org/jira/browse/HBASE-4489?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13126270#comment-13126270
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Nicolas Spiegelberg commented on HBASE-4489:
--------------------------------------------
@Dave:
I think the main disconnect here how is we envision accomplishing the goal of
'better key splitting'. I think your patch provides a different way to split.
However, both algorithms provide a splitting algorithm but do not provide an
easy way to normalize your row into this keyspace. We both assume you are
instinctively normalizing to begin with. I was suggesting adding a static
normalization function to both algorithms, in addition to the comments you
provided.
I still think that keeping the algorithm as ASCII would be better for
readability & usage.
1. Basically, we're telling users that they need to learn the JRuby byte
translation API to issue get commands from the shell if they follow the
UniformSplit strategy. I use the shell far more than I create new tables.
2. It's 8 bits per nibble. The 2x savings will go away with Delta Encoding &
naively using the default UINT128 sha1 would take up more space and be less
compressible than an ASCII UINT32 anyways.
> Better key splitting in RegionSplitter
> --------------------------------------
>
> Key: HBASE-4489
> URL: https://issues.apache.org/jira/browse/HBASE-4489
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.90.4
> Reporter: Dave Revell
> Assignee: Dave Revell
> Attachments: HBASE-4489-branch0.90-v1.patch,
> HBASE-4489-branch0.90-v2.patch, HBASE-4489-branch0.90-v3.patch,
> HBASE-4489-trunk-v1.patch, HBASE-4489-trunk-v2.patch,
> HBASE-4489-trunk-v3.patch
>
>
> The RegionSplitter utility allows users to create a pre-split table from the
> command line or do a rolling split on an existing table. It supports
> pluggable split algorithms that implement the SplitAlgorithm interface. The
> only/default SplitAlgorithm is one that assumes keys fall in the range from
> ASCII string "00000000" to ASCII string "7FFFFFFF". This is not a sane
> default, and seems useless to most users. Users are likely to be surprised by
> the fact that all the region splits occur in in the byte range of ASCII
> characters.
> A better default split algorithm would be one that evenly divides the space
> of all bytes, which is what this patch does. Making a table with five regions
> would split at \x33\x33..., \x66\x66...., \x99\x99..., \xCC\xCC..., and
> \xFF\xFF.
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