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https://issues.apache.org/jira/browse/HBASE-14468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14935434#comment-14935434
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Vladimir Rodionov commented on HBASE-14468:
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Yes, FIFO compactor does only one job: collects expired store files. I see many
applications for this policy:
# use it for very high volume raw data which has low TTL and which is the
source of another data (after additional processing). Example: raw event stream
(FIFO compaction) - compacted event stream (regular compaction)
# use it for data which can be kept entirely in a a block cache (RAM/SSD). Say
we have local SSD (1TB) which we can use as a block cache. No need for
compaction of a raw data at all.
> Compaction improvements: FIFO compaction policy
> -----------------------------------------------
>
> Key: HBASE-14468
> URL: https://issues.apache.org/jira/browse/HBASE-14468
> Project: HBase
> Issue Type: Improvement
> Reporter: Vladimir Rodionov
> Assignee: Vladimir Rodionov
> Fix For: 2.0.0
>
> Attachments: HBASE-14468-v1.patch, HBASE-14468-v2.patch
>
>
> h2. FIFO Compaction
> h3. Introduction
> FIFO compaction policy selects only files which have all cells expired. The
> column family MUST have non-default TTL. One of the use cases for this policy
> is when we need to store raw data which will be post-processed later and
> discarded completely after quite short period of time. Raw time-series vs.
> time-based rollup aggregates and compacted time-series. We collect raw
> time-series and store them into CF with FIFO compaction policy, periodically
> we run task which creates rollup aggregates and compacts time-series, the
> original raw data can be discarded after that.
> See: https://github.com/facebook/rocksdb/wiki/FIFO-compaction-style
> h3. To enable FIFO compaction policy
> For table:
> {code}
> HTableDescriptor desc = new HTableDescriptor(tableName);
>
> desc.setConfiguration(DefaultStoreEngine.DEFAULT_COMPACTION_POLICY_CLASS_KEY,
> FIFOCompactionPolicy.class.getName());
> {code}
> For CF:
> {code}
> HColumnDescriptor desc = new HColumnDescriptor(family);
>
> desc.setConfiguration(DefaultStoreEngine.DEFAULT_COMPACTION_POLICY_CLASS_KEY,
> FIFOCompactionPolicy.class.getName());
> {code}
> h3. Limitations
> Do not use FIFO compaction if :
> * Table/CF has MIN_VERSION > 0
> * Table/CF has TTL = FOREVER (HColumnDescriptor.DEFAULT_TTL)
> * Table/CF is MOB
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