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Lars Hofhansl commented on HBASE-14468: --------------------------------------- Haven't looked at the patch, but the idea sounds great! Does that mean we will essentially stay at memstore sized HFiles until they are collected? > 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 -- This message was sent by Atlassian JIRA (v6.3.4#6332)