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From "Vladimir Rodionov (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-14326) HBase book: fix definition of max min size to compact
Date Thu, 27 Aug 2015 20:50:46 GMT
Vladimir Rodionov created HBASE-14326:

             Summary: HBase book: fix definition of max min size to compact
                 Key: HBASE-14326
                 URL: https://issues.apache.org/jira/browse/HBASE-14326
             Project: HBase
          Issue Type: Bug
          Components: documentation
            Reporter: Vladimir Rodionov
             Fix For: 2.0.0

I think we need to change wording/definition of these config parameters in HBase book, they
are misleading:
A StoreFile smaller than this size will always be eligible for minor compaction. HFiles this
size or larger are evaluated by hbase.hstore.compaction.ratio to determine if they are eligible.
Because this limit represents the "automatic include"limit for all StoreFiles smaller than
this value, this value may need to be reduced in write-heavy environments where many StoreFiles
in the 1-2 MB range are being flushed, because every StoreFile will be targeted for compaction
and the resulting StoreFiles may still be under the minimum size and require further compaction.
If this parameter is lowered, the ratio check is triggered more quickly. This addressed some
issues seen in earlier versions of HBase but changing this parameter is no longer necessary
in most situations. Default: 128 MB expressed in bytes.
A StoreFile larger than this size will be excluded from compaction. The effect of raising
hbase.hstore.compaction.max.size is fewer, larger StoreFiles that do not get compacted often.
If you feel that compaction is happening too often without much benefit, you can try raising
this value. Default: the value of LONG.MAX_VALUE, expressed in bytes.

For details, see HBASE-14263.

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