[jira] [Created] (HBASE-9243) Add more useful statistics in the HFile tool

["Alexandre Normand (JIRA)" <ji...@apache.org>]

Alexandre Normand created HBASE-9243:
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             Summary: Add more useful statistics in the HFile tool
                 Key: HBASE-9243
                 URL: https://issues.apache.org/jira/browse/HBASE-9243
             Project: HBase
          Issue Type: Improvement
          Components: HFile
    Affects Versions: 0.96.0
            Reporter: Alexandre Normand
            Priority: Minor


The [HFile tool|http://hbase.apache.org/book/regions.arch.html#hfile_tool] has been very useful to us recently to get a better idea of the size of our rows. However, it happened frequently that we wished for more statistics to have a more complete picture of the distribution of the row sizes. 

[~skuehn] requested that feature often enough in private that I decided to give it a go. 

Here's the patch that adds more nice little stats via yammer's histograms. It was easy enough since {{com.yammer.metrics}} is already in hbase's dependencies.

Example of the new output from {{org.apache.hadoop.hbase.io.hfile.HFile -s -f ...}}:
{code}
Stats:
	Key length:
               min = 24.00
               max = 24.00
              mean = 24.00
            stddev = 0.00
            median = 24.00
              75% <= 24.00
              95% <= 24.00
              98% <= 24.00
              99% <= 24.00
            99.9% <= 24.00
	Row size (bytes):
               min = 33.00
               max = 33.00
              mean = 33.00
            stddev = 0.00
            median = 33.00
              75% <= 33.00
              95% <= 33.00
              98% <= 33.00
              99% <= 33.00
            99.9% <= 33.00
	Row size (columns):
               min = 1.00
               max = 1.00
              mean = 1.00
            stddev = 0.00
            median = 1.00
              75% <= 1.00
              95% <= 1.00
              98% <= 1.00
              99% <= 1.00
            99.9% <= 1.00
	Val length:
               min = 1.00
               max = 1.00
              mean = 1.00
            stddev = 0.00
            median = 1.00
              75% <= 1.00
              95% <= 1.00
              98% <= 1.00
              99% <= 1.00
            99.9% <= 1.00
Key of biggest row: \x00
{code}  

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