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https://issues.apache.org/jira/browse/HBASE-16608?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Anastasia Braginsky updated HBASE-16608:
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Release Note:
The index-compation and data-compaction variants of CompactingMemStore are
introduced. In both types the active (mutable) segment is periodically
flushed-in-memory and is added as immutable segment in the compaction pipeline.
The CompactingMemStore of index-compaction type is merging all immutable
segments of the compacting pipeline into one. The merging of N segments is
explained below. The CompactingMemStore of data-compaction type is compacting
all immutable segments of the compacting pipeline into one. After the
merge/compaction the old segments in the compacting pipeline are replaced with
one new.
Before explaining the process of merging N old segments into new one, note that
segment structure includes ordered index that allows traversing the cells data
efficiently. The merge is copying the ordered indexes of the old segments into
one ordered index of new segment. No data is copied, no cells are filtered.
Alternatively, in the process of compacting N old segments into new one, both
data and index are copied. The old cells are filtered, meaning upon compaction
unused versions of the cells are not copied so the new segment has less data
then all old ones.
This issue introduces only the merging ability and simplifies the user
intervention for switching between types. The previous CompactingMemStore
structure was added by HBASE-16420 and HBASE-16421. The future refinements of
the policy or merging/compacting will come in HBASE-16417.
In order to create a table with CompactingMemStore as a MemStore one should use:
create ‘<tablename>’, {NAME => ‘<cfname>’, IN_MEMORY_COMPACTION => true}
IN_MEMORY_COMPACTION default is false, so table created as following will have
the known DefaultMemStore as a MemStore.
create ‘<tablename>’, {NAME => ‘<cfname>’}
The default type of CompactingMemStore is index-compaction. In order to change
it to data-compaction one should add to the hbase-site.xml
<property>
<name>hbase.hregion.compacting.memstore.type</name>
<value>data-compaction</value>
</property>
in addition to creating the table as following
create ‘<tablename>’, {NAME => ‘<cfname>’, IN_MEMORY_COMPACTION => true}
> Introducing the ability to merge ImmutableSegments without copy-compaction or
> SQM usage
> ---------------------------------------------------------------------------------------
>
> Key: HBASE-16608
> URL: https://issues.apache.org/jira/browse/HBASE-16608
> Project: HBase
> Issue Type: Sub-task
> Affects Versions: 2.0.0
> Reporter: Anastasia Braginsky
> Assignee: Anastasia Braginsky
> Fix For: 2.0.0
>
> Attachments: HBASE-16417-V02.patch, HBASE-16417-V04.patch,
> HBASE-16417-V06.patch, HBASE-16417-V07.patch, HBASE-16417-V08.patch,
> HBASE-16417-V10.patch, HBASE-16608-Final.patch, HBASE-16608-Final.patch,
> HBASE-16608-V01.patch, HBASE-16608-V03.patch, HBASE-16608-V04.patch,
> HBASE-16608-V08.patch, HBASE-16608-V09.patch, HBASE-16608-V09.patch
>
>
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