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https://issues.apache.org/jira/browse/HBASE-14326?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Misty Stanley-Jones updated HBASE-14326:
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Status: Patch Available (was: Open)
> 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
> Assignee: Misty Stanley-Jones
> Fix For: 2.0.0
>
> Attachments: HBASE-14326.patch
>
>
> I think we need to change wording/definition of these config parameters in
> HBase book, they are misleading:
> {quote}
> hbase.hstore.compaction.min.size
> Description
> 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.
> Default
> 134217728
> hbase.hstore.compaction.max.size
> Description
> 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.
> hbase.hstore.compaction.ratio
> Description
> For minor compaction, this ratio is used to determine whether a given
> StoreFile which is larger than hbase.hstore.compaction.min.size is eligible
> for compaction. Its effect is to limit compaction of large StoreFiles. The
> value of hbase.hstore.compaction.ratio is expressed as a floating-point
> decimal. A large ratio, such as 10, will produce a single giant StoreFile.
> Conversely, a low value, such as .25, will produce behavior similar to the
> BigTable compaction algorithm, producing four StoreFiles. A moderate value of
> between 1.0 and 1.4 is recommended. When tuning this value, you are balancing
> write costs with read costs. Raising the value (to something like 1.4) will
> have more write costs, because you will compact larger StoreFiles. However,
> during reads, HBase will need to seek through fewer StoreFiles to accomplish
> the read. Consider this approach if you cannot take advantage of Bloom
> filters. Otherwise, you can lower this value to something like 1.0 to reduce
> the background cost of writes, and use Bloom filters to control the number of
> StoreFiles touched during reads. For most cases, the default value is
> appropriate.
> Default
> 1.2F
> {quote}
> For details, see HBASE-14263.
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