[jira] [Created] (HBASE-17241) Avoid compacting already compacted mob files with _del files

["huaxiang sun (JIRA)" <ji...@apache.org>]

huaxiang sun created HBASE-17241:
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             Summary: Avoid compacting already compacted  mob files with _del files
                 Key: HBASE-17241
                 URL: https://issues.apache.org/jira/browse/HBASE-17241
             Project: HBase
          Issue Type: Improvement
          Components: mob
    Affects Versions: 2.0.0
            Reporter: huaxiang sun
            Assignee: huaxiang sun


Today if there is only one file in the partition, and there is no _del files, the file is skipped. With del file, the current logic is to compact the already-compacted file with _del file. Let's say there is one mob file regionA20161101***, which was compacted. On 12/1/2016, there is _del file regionB20161201**_del, mob compaction kicks in, regionA20161101*** is less than the threshold, and it is picked for compaction. Since there is a _del file, regionA20161101**** and regionB20161201***_del are compacted into regionA20161101**_1 . After that, regionB20161201**_del cannot be deleted since it is not a allFile compaction. The next mob compaction, regionA20161101**_1 and regionB20161201**_del will be picked up again and be compacted into regionA20161101***_2. So in this case, it will cause more unnecessary IOs.



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