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https://issues.apache.org/jira/browse/HBASE-4489?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13125118#comment-13125118
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Jonathan Hsieh commented on HBASE-4489:
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@Dave
Part of me really just would prefer decouple rollingSplit from the presplit
min/max value selection -- maybe change this in to two programs -- a custom
presplit table generator program that handles key bounds, and a separate
rollingSplit program that just splits based on given key ranges.
I thought that there was agreement that we would keep MD5StringSplit as default
for 0.90. It looks like the default was changed to UniformSplit from
MD5StringSplit in both patches. While I generally agree with your point #3,
it is a in 0.90 and would be a compatibility problem for anyone who depends on
it. Would it make sense to change the default in trunk/0.92 (I'm fine with
that) but leave 0.90.x as is?
Nice functional test. Did you consider just doing a unit test on the split
algorithm along with the cluster spinning functional test? I believe
HBaseAdmin.create(HTableDescriptor htd,byte startKeys[][]) is well tested and
would make the non @Ignored portions quicker. I can see how you need this
setup for testing rollingSplit.
Interesting div 0 bug. More testing, less surprises!
Any reason why in testCreatePressplitTable you go to -0x71, 0x81 .. -0x11
instead of just going to 0x8f, 0x9f .. 0xff? Though more verbose, I think it
is easier to read and follow if you use "positive" hex and cast all of them
with (byte), or write out single longs and convert?
> 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-trunk-v1.patch,
> HBASE-4489-trunk-v2.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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