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https://issues.apache.org/jira/browse/HBASE-17172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15874003#comment-15874003
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Jingcheng Du commented on HBASE-17172:
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Thanks [~huaxiang] for the patch. Sorry for the late response.
bq. // TODO: is it possible to skip read of most hfiles?
Most of mob files are compacted by the same start key, and lots of different
first/last keys are grouped together. Thus using both first and last keys
groups del files is not necessary and is a waste, right?
Do we have a way to group them only by the start key from the name? Since now
we have always retained the delete markers in hfiles, I think it is okay to do
in this way?
Thanks!
> Optimize mob compaction with _del files
> ---------------------------------------
>
> Key: HBASE-17172
> URL: https://issues.apache.org/jira/browse/HBASE-17172
> Project: HBase
> Issue Type: Improvement
> Components: mob
> Affects Versions: 2.0.0
> Reporter: huaxiang sun
> Assignee: huaxiang sun
> Fix For: 2.0.0
>
> Attachments: HBASE-17172-master-001.patch,
> HBASE-17172.master.001.patch, HBASE-17172.master.002.patch,
> HBASE-17172.master.003.patch
>
>
> Today, when there is a _del file in mobdir, with major mob compaction, every
> mob file will be recompacted, this causes lots of IO and slow down major mob
> compaction (may take months to finish). This needs to be improved. A few
> ideas are:
> 1) Do not compact all _del files into one, instead, compact them based on
> groups with startKey as the key. Then use firstKey/startKey to make each mob
> file to see if the _del file needs to be included for this partition.
> 2). Based on the timerange of the _del file, compaction for files after that
> timerange does not need to include the _del file as these are newer files.
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