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https://issues.apache.org/jira/browse/HBASE-7342?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13530472#comment-13530472
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Ted Yu commented on HBASE-7342:
-------------------------------

There're compilation error:
{code}
[ERROR] Failed to execute goal 
org.apache.maven.plugins:maven-compiler-plugin:2.5.1:testCompile 
(default-testCompile) on project hbase-server: Compilation failure: Compilation 
failure:
[ERROR] 
/Users/zhihyu/trunk-hbase/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java:[40,30]
 cannot find symbol
[ERROR] symbol  : class HServerAddress
[ERROR] location: package org.apache.hadoop.hbase
[ERROR] 
/Users/zhihyu/trunk-hbase/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java:[763,21]
 cannot find symbol
[ERROR] symbol  : class HServerAddress
[ERROR] location: class 
org.apache.hadoop.hbase.regionserver.TestSplitTransactionOnCluster
[ERROR] 
/Users/zhihyu/trunk-hbase/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java:[763,48]
 cannot find symbol
[ERROR] symbol  : method getRegionsInfo()
[ERROR] location: class org.apache.hadoop.hbase.client.HTable
[ERROR] 
/Users/zhihyu/trunk-hbase/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java:[772,17]
 cannot find symbol
[ERROR] symbol  : method getRegionsInfo()
[ERROR] location: class org.apache.hadoop.hbase.client.HTable
{code}
HServerAddress is replaced by ServerName in trunk.
getRegionsInfo() is replaced by getRegionLocations.
                
> Split operation without split key incorrectly finds the middle key in 
> off-by-one error
> --------------------------------------------------------------------------------------
>
>                 Key: HBASE-7342
>                 URL: https://issues.apache.org/jira/browse/HBASE-7342
>             Project: HBase
>          Issue Type: Bug
>          Components: HFile, io
>    Affects Versions: 0.94.1, 0.94.2, 0.94.3, 0.96.0
>            Reporter: Aleksandr Shulman
>            Assignee: Aleksandr Shulman
>            Priority: Minor
>             Fix For: 0.96.0, 0.94.4
>
>         Attachments: HBASE-7342-v1.patch
>
>
> I took a deeper look into issues I was having using region splitting when 
> specifying a region (but not a key for splitting).
> The midkey calculation is off by one and when there are 2 rows, will pick the 
> 0th one. This causes the firstkey to be the same as midkey and the split will 
> fail. Removing the -1 causes it work correctly, as per the test I've added.
> Looking into the code here is what goes on:
> 1. Split takes the largest storefile
> 2. It puts all the keys into a 2-dimensional array called blockKeys[][]. Key 
> i resides as blockKeys[i]
> 3. Getting the middle root-level index should yield the key in the middle of 
> the storefile
> 4. In step 3, we see that there is a possible erroneous (-1) to adjust for 
> the 0-offset indexing.
> 5. In a result with where there are only 2 blockKeys, this yields the 0th 
> block key. 
> 6. Unfortunately, this is the same block key that 'firstKey' will be.
> 7. This yields the result in HStore.java:1873 ("cannot split because midkey 
> is the same as first or last row")
> 8. Removing the -1 solves the problem (in this case). 

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