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From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-15477) Do not save 'next block header' when we cache hfileblocks
Date Thu, 17 Mar 2016 19:43:33 GMT
stack created HBASE-15477:
-----------------------------

             Summary: Do not save 'next block header' when we cache hfileblocks
                 Key: HBASE-15477
                 URL: https://issues.apache.org/jira/browse/HBASE-15477
             Project: HBase
          Issue Type: Sub-task
          Components: BlockCache, Performance
            Reporter: stack
            Assignee: stack


    When we read from HDFS, we overread to pick up the next blocks header.
    Doing this saves a seek as we move through the hfile; we save having to
    do an explicit seek just to read the block header every time we need to
    read the body.  We used to read in the next header as part of the
    current blocks buffer. This buffer was then what got persisted to
    blockcache; so we were over-persisting wrtiting out our block plus the
    next blocks' header (overpersisting 33 bytes). Parse of HFileBlock
    complicated by this extra tail. Fix.



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